Whats the reason why i get dizzy after sex? i feel like i'm gonna pass out and was sweating cold...

Just relax: There's a lot more work that you perform during sex than you realize. Perhaps, you're not as well hydrated. The cold sweating component suggests a vasovagal element which refers to blood pressure changes after heavy physical exertion or postural changes. I suggest you check your diet, hydration status and just RELAX a bit after your activities instead of getting up right away to do "stuff.."