can't cum more than once?

Monie
i've realized that i can't cum more than once in a row. many girls tell me that "they can orgasm maybe eight times in one sitting," but i feel like i can only reach it once before i completely die out. i normally last about 3-5 minutes before i orgasm, but after that i feel completely used out, and i can't reach it again. even if i take a break for an hour or so but try to masturbate again, it feels impossible! is this normal? do you guys think i'm doing something wrong? it feels great while it's happening, but i feel so died out afterwards and it feels like it would be impossible to reach it again.