I believe you should seek counseling. It will help you ease your anxiety. To get comfortable with yourself. I really advise it. It's always best to start asap. I never sought help when I had issues, and they snowballed into these horrible emotions and state of mind.
I've done that too, wait on messages,emails, texts...that invitation, for that person to walk through my front gate and sometimes it's for the best.
I'm sure you dont want to hear that--but if people do put you off because they don't care, make new friends. And that sounds hard--but really you should talk to everyone. Meet people...eventually you'll meet the right people to be friends with.
Please know that many friendships in highschool end, you should remember that in this life people come and go. Don't feel sad that you can't maintain a relationship--at first I did , but we just have such busy schedules that its so hard to keep in touch.
--It takes time to meet good friends, but more than that it is the people you seek out. You're in High school, everyone right now is trying to fit in, their emotions are running wild, their hormones are raging, there are so many people out there feeling just like you. Everyone is feeling chaotic, --just know that your not alone.
--but also know that sometimes people are simply busy and don't mean to ignore you.