Am I orgasming........?

Ok so I'm kinda new to master bating and I want to know am I orgasming? So when I get to that point I start violently hip thrusting and get outta breath and it's kind of invoulentary, I don't do anything it just happens. But I'm not sure if it's really an orgasm because I've read up on it and I've read it usually takes awhile to get to that point and for me I can get there within a few minutes and it doesnt last long at all like less than a minute...so is it an orgasm? And if it is any tips to make it last longer?