Orgasm questions....girlss only!!?

So me and my bf have been having sex for like 2 years and I always thought he made me orgasm here and there but recently I felt something beyond what I've felt before and he said my moans changed and everything and I was breathing heavy and uhh it just felt soo good. But now I'm confused cuz thts happened twice now soo was tht an orgasm? Have I been mistaken this whole time? How do u know if ur having an orgasm?