New to sex

Okay so im new to sex and im always overthinking stuff. I was on my period Jan 23-28 and I had intercourse 2-3 days after my period. My period tracker says im in my fertile window aka ovulation. When we have sex, we don’t wear a condom for the first few minutes. But then we end up putting one on after about 6-10min in. Side note: Our whole intercourse lasts up to 2 hours. Now my problem is that he didnt even know that pre-nut even existed and I don’t know how that’s supposed to feel like, so I’m not sure if that fluid was even in me before getting the chance to put a condom on. But he didn’t nut in me. He says we should be fine as in regards to pregnancy but you never know what could go wrong. So is there a possibility of me getting prego?