Who’s my BABY DADDY?!

Okay I messed up big time and I need advice. So me and my sons father split up and I had kinda been seeing some one. We were not “official” and he knew things had been really messy with my sons father but we were still gonna try things out. Well let me give some details... I’m breastfeeding so I hadn’t had my period for ten months. Well I had finally got it back and I only had two periods. Well I obviously use glow to track everything, including when I had sex. I didn’t know if my “ovulation week” was really 100% accurate yet because like I said I had only had two periods and I hadn’t really been tracking it yet. Well my dumbass had a moment of weakness and has sex with my ex on May 13-14 which I didn’t put in glow for some reason so part of me feels like it didn’t happen but I drank and it’s starting to come back to me... well that was supposedly during my ovulation week... he pulled out and we have been successful with that method for almost 2 years. (As in no babies until we wanted one) well me and the guy I’ve been seeing had sex on the May 20th, I was on top, it was hot and I’m pretty sure he didn’t pull out in time.... and the first time we had sex he was freaking out telling me to get plan b he didn’t think he pulled out fast enough... so 10 days later Or whatever on June 1st im supposed to start my period.... RED FLAGS. I don’t effing start. Well I know I’m pregnant. I just know it. I waited like 2 days and I take a test..... and there it is BARLEY... you’d think I was crazy if I didn’t already know in my gut I was pregnant, so I made and appt. and I tell the doctor my situation as embarrassing and shameful as it is. According to my LMP my conception date would’ve been May 13-14 but when we did the ultrasound he said according to the baby’s size my conception date would me May 20th. SO WHAT THE FUCK. I know I probably sound like a big ass hoe and I’m not, I just made a mistake and I’m so embarrassed but I don’t want to be that mom who doesn’t know who her child’s father is and I also don’t want to go an entire pregnancy telling this guy it’s his if it isn’t. I really care for him and at first I knew for damn sure it was his and now it’s 4AM I can’t sleep and I just need someone to say something to me other than paternity testing 😭