Masturbation/orgasm help

Alright so when I masturbate I only touch my clit and it feels really good. But I do it until I get this feeling that makes me like shake and than I get kinda sweaty and I also get pretty wet right after. It feels really good so I'm guessing that's an orgasm? But what I'm asking is it literally only takes me one minute or less to get to this sensation and after I hit it, I'm done. Like I don't want to keep going, it almost makes me feel sick if I do. I do it multiple times a day because it feels so good, but I'm just confused why it literally takes no time to get there and than right after the sensation I'm done. Is that normal? I hear people say they have multiple orgasms but if this is one, I can only have one. Not multiple