Could I be pregnant?

I had sex with my boyfriend over a week ago with a used condom...he didn’t cum in it the first time we used it (we were only having sex for 2 minutes the first time we used that condom but stopped because we heard people come home). I know you should never use a condom twice but we had only had that one and we were both extremely turned on that evening. We both realise this was stupid and not a risk we should take as I’m 18 and still in school. We didn’t want to use the pull out method because he usually pre-ejaculates quite a bit. I am not on any other form of birth control and we only use condoms to prevent pregnancy (we were both virgins prior and so we aren’t concerned about contracting STDs).

Am I just over-thinking this because this happened during the 3rd time we’d both ever had sex and this is fairly new to me? Is it normal to panic like this when you first start having sex?

Help and advice would be much appreciated.