I just feel so off

It's a very big situation but I feel like letting it out will make me feel sort of better. I hope I don't get judged for this, but yeah I made the stupid decision to have an online relationship. I'm a teenager. We just met through a game and we started chatting on discord and everything was dreamy. Same interests, same energy, same everything. We were so excited with each other and we instantly both fell head over heels. They asked me to be their boyfriend a week after and we had a relationship for around 8 months. Everything was fine. No hidden creep situation. We are both the same age and we face timed, called and texted all the time. Everything was amazing. We even planned to meet since they were from Germany and my father also went there for a while. Untill my mother get hysterical about me using my phone that much. She took it. She went through my messages. She found everything and instead of talking with me and confronting me gently (because I had used my chosen name with my then partner) she put restrictions on my phone and yelled at me. She took everything for me. She ruined it all. After that I had to find very sneaky ways to talk with my then partner. Many stupid ways. Through Spotify, through some bad quality karaoke app. That whole situation made me realize many things about my mother and father (he always played the good one around me, but was especially cruel with this situation. Felt like betrayal) so I extremely stressed. I had them on my mind all day and apparently, I came off as mentally unstable. I was, I agree, but I didn't mean to come off creepy or dependent on them. One day, out of the blue, they asked me to break up. I don't even remember what the message said. It absolutely wrecked me. I asked them if we could at least stay friends, I couldn't handle loosing them. We tried. At least I tried. But as you can guess even if I tried to hold myself back I was affectionate at them still. I couldn't help it. And I didn't mean to hurt them. It just came off naturally. And they reciprocated sometimes, but they were mostly dry as fuck with me. Which hurt me. After a month or two, they asked me to cut contact. They said this whole thing feels like a relationship and it isn't helping their situation. And they weren't gentle with it. They said it harsh and clear (specifically, I said "it's alright, don't be sorry. I hope some time I can make this up to you" and they said "don't say that. We won't talk ever again. Don't have such Motives"). I of course said it's alright and we agreed not to block each other and just leave it like that. When I tell you I was a wreck, I am not over reacting. Over the next month I couldn't eat. I sat down to do so, appetite instantly went away. I had to go inside the bathroom and lock myself multiple times a day so that I could cry in peace since my mother was still a pain in the ass. I dropped weight instantly and felt weak. I stopped talking to my friends as much and I became a snappy and on edge person. I am not like that. Until I couldn't handle it anymore. A month after we broke contact it was their birthday and of course I remembered. I didn't want to contact them because I felt extremely anxious since they had told me that we shouldn't talk ever again. But I was stupid and dumb. I remembered they had a YouTube channel, so I went ahead and commented "hey (name), I'm sorry for the sudden contact. I'd just like to wish you a happy birthday." And signed with my name. To my surprise, they instantly replied and asked me if I wanted to talk again. I got excited unfortunately and said yes. Little did I know it was going to be hell. We took some time to catch up and it just...seemed like everything was suddenly falling into place again. We talked for hours again every day. Endless topics. It was a dream for a few days again. Until they mentioned a person that they liked. They had fallen for another person and needed my advice to get with them. (Mind you, I was already attaching myself to them again. Getting false hope that things might get better again) So I sucked it up and gave advice. Over the next weeks I went through everything to not show them how it truly makes me feel. In the end, they got rejected by the person. And I feel Terrible to say I was happy. I know it's bad. I know that It is such a wrong thing to be happy over something like that but I'm just now noticing how unstable I was. Something happened after that rejection, and I noticed that they were desperate for any love from anyone. It's quite normal, since they have been through a lot themselves, but one night made it worse. We were chatting and we just both snapped after unexpectedly being a little sweet with each other. We talked about how we feel and they admitted that they have some complicated feelings for me. That they were also holding back pet names and we agreed to not hold back. For the rest of the night we acted sweet and it was the first time in months I slept more than 6 hours and slept amazingly. I fell asleep without crying. The next morning though, they came back to me talking about another person. They had fallen for someone else. A new guy they met. I was destroyed. I couldn't hold it in and called them out for it. I told them how that whole thing made me feel and I told them that I want to be clear with my feelings and wrote a paragraph about my feelings towards them. They said we should stay friends, and that they are feeling confused at the moment. Everything sweet stopped after that. Now, they have found a third person. Since the other guy thought of them as a friend. It is another person now. A girl. Different than the others. It is destroying me piece by piece every day. They have fallen for her beyond what I can describe. What they say about her is so poetic and...just like what they used to say to me. Songs they used to say reminded them of me, now remind them of her. And they tell me everything without knowing how much I hurt. Such things as "I think I have genuinely found my soulmate in a sense" and "we both admitted we have been waiting for a person like each other forever". I know it is a horrible situation but I don't know what the hell to do. I can't leave them. And we seem to be falling apart. Talking not even half as much as we used to. Just a few minutes of texting a day. And it feels horrible now. They always talk about her only. They say they can only be themselves around her. I know I shouldn't feel like that since we are not together anymore, but that used to be me. I was that person once. It has been 6 months and I'm not over them. Any advice on what I should do at all?