How can I tell if I miss the HIM, or the IDEA of him and a relationship? I've always known to follow my heart, but right now I don't know. I don't wan to be that guy who goes after the one who may have gotten away, and then when I do I get nothing in return. We split because we got too serious too fast (in his eyes), and he never put in effort (in my eyes.) It has literally been 10 days and I haven't gone a single day without thinking of him, or us. (How fucking highschool. fuck.) Thank you.
Relationships are something you can not rush, you need to understand that the person you are with might not be ready to take it to the next step yet. He might just want to be friends for now, get his feet wet, which is okay. If you really like him, you'll respect his space and let him think about things for a while. Sure you can keep in contact and ask how everything is going but don't pressure him into doing anything he isn't ready for. I know getting over a relationship is difficult, but there will always be someone else out there, and as cliche is that sounds it's true.
Given that he is accusing you of moving too fast I'm guessing you like being in relationships, so you're probably missing the idea of being in a relationship. However if you've broken up with somebody you're likely to be missing them as well, so it's a combination of the two. Just hang in there and wait for it to get better.
I am sure you are missing him, but I agree with hands^, it is probably the relationship. Sure theres a chance you could get him back, and you could always rebound and get another guy, but I think you should just wait. Things will get better with time, I hate hearing that too, but they do. I think you should try being single for awhile, learn how to do that. Thats where I am at right now, its kind of new right now. I hope things do get better soon though.