Trouble Orgasming

I've been dating /having sex with this guy for two months, and I have yet to cum during sex. Nothing seems to work: we've tried multiple positions and oral but I rarely even come close to orgasming. Sometimes my clit even feels a bit numb, like nothing's happening. At first I was honest and answered him truthfully every time he asked if I finished, but now I just feel awkward and bad so I've started faking it once in a while. Part of me thinks I'm putting too much ressure on myself to cum, but it's hard to not think about it when you're in that situation. It also ocurred to me that maybe this is the casebecause he's the first guy I've ever dated/had sex with. What do you guys think? Any advice? Thanks xx