Pregnancy scare???

Im super stressed but I’m not sure if I need to be. I over analyze when it comes to things like this but, I’ve been sleeping with my ex again and I mean we are friends and all. Lately he’s been having baby fever and he is 27 and I’m 20. I know if we were to have one he’d be fine with it but I’m not there yet ahhhhhhh. We had sex five times on Friday, today is Tuesday, and every one of those times he finished inside me. I have the implant and it’s normal that my period isn’t consistent so I try not to worry. I’ve never used condoms with him when we were dating and still have yet to use them. My implant has been very useful and has never failed so far. I am 2 days late to what eve predicted my next period would be, regardless of having sex or not it’d still most likely be late, but I’m an over thinker. Advice? Should I tell him that I’m nervous about it? I just don’t want to drive him away again.