What should I do with this guy I really like?

Pleasee help me ! I am SOOO upset right now it feels like I am having an anxity attack. We started talking like a week ago and we text everyday and we tlked on the phone and he said he liked me and I said I liked him. we hung out yesturday blah blah blah buuut yesturday.. he was texting andd sometimes wehn I looked over he wouldn turn his phone away..?whys he doin that . anddd if it makes a differnece im 15 and hes 17 && he texted me today but its different what he texted me today then it was from a week ago. A week go he was texting me thigns like long sentences now there things oike “okay””ight””lol” and im scareddd. On eof my friends that knows his kinna well says tat he is 2 faced to girls only to try and get in there pants. and like I REAAALy like him I had a lot of boyfriends before but I have never felt like this before like I do for him.

pleaseee helpp.mee(:!