Orgasm?

When I masturbate I mainly just play with my clit bc it seems to work best for me, so after a little while I’ll get to this place where I’m shaking and moving involuntarily. It’s pretty intense and I feel like going on would be too much, but I also feel like I’m at the cusp of orgasm and should just power on bc I want to experience that. Is it possible that I actually did orgasm and don’t know it, or is it really obvious when it happens?