Is It Possible To Get Pregnant While Using A Condom, Or Did It Likely Occur During Unprotected Intercourse?

Hello Doctor! I am a 32years old lady. I had a physical relationship with my partner on 14th Oct 21 using protection/male condom. It was for a long duration like 2hrs. The very next a I had a sudden intercourse with another partner without any protection, for a shorter duration , like 30mins. By the very next month I discovered that I m pregnant. I just want to know, is it possible to get conceived inspite of having a protection? or it happened the day I was not using the protection. How to confirm?