please help me!

Being a girl born and raised in a catholic school and community, I constantly find myself not knowing what to do what it comes to pregnancy and sex Ed. So I need help! My boyfriend and I have sex often, and we always use a condom, and he even doesn't cum in me with a condom on. He also ALWAYS does the water test after. We're very careful! We've never had sex on a day in which I was ovulating, but we recently had sex during my fertile window. My period is in 3 days so I can't say for sure! But I always psych myself out and think I'm pregnant! It is finals week for me so I'm also super stressed. If we had sex during my fertile window, on a day where I WASN'T ovulating, but he didn't cum in me AND he was wearing a condom, how possible is it that I'm pregnant? Just asking to calm myself down! I don't think I am but I really need some help to know for sure. I'm definitely going on the pill but not until I'm home!