I Am Confused About My Feelings

I recently broke up with my girlfriend, whom I've been with for over 6 years... I made that decision, I knew that the relationship was doomed for some time, but I just kept going, I kept trying to ignore its problems, even though some of them were heavily impacting me, such as her having issues with my family…

I ended up taking the final decision to break up, but that doesn’t stop me from thinking about it every day, I really miss her, I don’t think I’ve ever felt so lonely in my life to be quite frank… It was a logical decision, not an emotional one…

Now I’m torn apart because of it… And being completely honest, I’m so messy that I’m not even sure I’m suffering more because I miss her, or if its because of loneliness in itself… I’m an introvert when it comes to personal relationships (like, I’m fine at work and all, just not really in personal relationships), which pretty much prevents me from even trying to get to know anyone else…

I have several other personal probems, but this is the one thing that's constantly on my mind, I’m just lost, I have no idea what to do with my life…