I really appreciate all of your input, honestly. Sometimes, I worry that a woman will think that I'm hitting on her when I'm just trying to be friendly. Is there anyway to prevent that besides just being friendly?
You just have to build it up slowly again. The more you are around people, the easier it will be. Start off by making friends with other guys. Go out and hang with those guys. I'm sure one of them has a girlfriend. Have casual convos with them. This is how you build up courage to talk to girls. I'm sure she'll have a friend or two that she'll hook you up with and do the same thing with the new girl. It's all about building up confidence. Just don't overthink it and you'll be fine. Remember, it's a process. It doesn't happen overnight.
I like what you said here; to be frank overthinking has been my Achilles Heel all my life. I've never been in a relationship, while all my friends are in one or have been in one, so it's a little weird for me sometimes. Recently, the whole being single thing hasn't been all that much of an issue (being busy with school and all) but the inability to talk is. So thanks for your advice; I think I just have to go into it and talk casually.