So, I met this guy who's about three years older than me through mutual friends on myspace. I had actually met him once before a couple years ago, but we didn't really remember. Anyway, after talking online for a while, last night we finally hung out, and had sex. Today he was online but IMed me about something I wrote about me losing my keys... he asked if I did and maybe they were in his car and blah blah, I was so nervous so I kept words to a minimum, and he didn't send anything else after the last IM. Was he just trying to be nice? Or are things awkward because neither of us know what to say? I know having sex with him so early was a mistake because I do have a crush on him, but now I'm worried he thinks I'm a slut and we'll just stop talking. What do I do? Does the three day rule apply to online stuff too? Is "so, you lost your keys?" an attempt to talk or just a little contact to be nice? He is nice and shy I think, he also assured me that he didn't care if I wasn't super skinny and he wasn't shallow. UGH. It's just all confusing. Thoughts? What should I be doing that would really work in my favor?

Well it can be anything, many guys will go out and see if they can "score" and if they do, lose interest. Does he have another girlfriend ?

I think you are reading way too much into nothing. He isn't avoiding you or anything like that so just take it as it comes and try to calm your nerves a little.

He got what he wanted, and will be back when he wants more.

well it can be anything, many guys will go out and see if they can "score" and if they do, lose interest. Does he have another girlfriend ?

He does not have another girlfriend, he is looking for someone to date right now I'm almost 100% sure.

Some insight in the situation...
I REALLY liked a girl.. online thing - much like yours.. we never hung out.. but I was so into her it was unbelievable.. I went to go see some old friends and I knew she was going to be there.. we ended up almost having sex.. she wanted to have sex and we could have, but that would mean I had to ditch my friends.. and I automatically thought.. (ok if she's that easy on the first night,ill just go out with my friends tonight and I can continue where we left off tomorrow - kind of sleezy I know,I'm sorry,I'm being honest).. anw.. point of the story is that she automatically deteorated(spelling? Too lazy :/) from my eyes, as I had her quite highly in my books , almost instantly.. so yes - you made a mistake by sleeping with him so quickly if you intended on having something more serious with him..
I know I haven't given you advice on this, I don't know what to say really ;/ just adding insight.