How to know if I had an orgasm?

Sometimes I think I come close, but I'm not sure it's ever actually happened. When I have sex with my boyfriend sometimes I start shaking (usually when I'm on top), but I don't know if that's quite it. When he fingers me/goes down on me it usually feels good up to a certain point where I feel like it's just so much sensation it's too much for me to handle and is almost painful. Sometimes we try to keep going because I wonder if that's what being on the edge of having an orgasm is like and he really wants to make me come and feel good, but I can't ever seem to get past that point. What can I do? Is that an orgasm? I don't think it is, I think it's being on the verge of one, but I just don't know...

What can I do? Any tips? Thank you so much 💕😊