Guy questions

I've been seeing this guy for about 3 or 4 weeks, well at first he was calling me beautiful and texting me every morning, well we hung out, and I know this is frowned upon, but I shower with him, and had sex on the first "date", I told him I never do that, and he told me not to worry, well we continued talking, but now he doesn't really text me. I don't know if it's because he's been working alot, or what, but now he only snapchats me, and after awhile ignores me.. I did some research and it says to give him space? but I'm afraid if I do, he might leave, and I really like this guy.. anything advice helps.. thank you.