I have questions please answer!!

I just recently lost my virginity but still have a couple questions..

So when I was having sex, we were outside in a cold shed building and yes it was furnished but had no electricity.. So I was wondering why his legs were shaking when I was giving him head?? Was he cold or is there another explanation?

Another question is how can the condom break super easily? We wernt going very hard at all and he thinks its because I was "too tight" but idk if there is such thing as that.. It's not like he was too big. Did we not have enough lube?

Another question, it felt good to have sex but it didn't feel so good that I orgasmed, I didn't even get close but of course he did and even came which could have been 'pre cum' but that is a new term to me and I don't understand what exactly it is.. Please please help because I don't understand.