is it an orgasm or do I have to pee?

When I was using a vibrator for the first time last night, this feeling came over me all of a sudden. My legs were shaking and my vagina was pulsing. Then, it felt like I had to pee. Thinking it was that, I held it and it went away after a while. Now I'm wondering if it was an orgasm or if I really did have to pee