Dating woes....after sex...

So Ive met this most amazing man. We get along, like a house on fire. So much jn common and we can chat for hours on the phone. We've been dating for a bit and this past weekend for the 1st time I slept over at his and we had sex many times. We had a good time and the following day we texted... but I got a weird vibe... usually when I get this vibe it means somethings not right... so today he's barely talked to me and we talk so much usually and now im starting to think it was the sex... I also have bad experiences of this happening and I dont know if I'm also projecting or he just might be genuinely busy... I just feel anxious I guess, because I've really opened my heart to him... and now I feel I've done something wrong... Thoughts?!?!