I have sex with my boyfriend and he cums in me every time and a lot comes out and i usually go pee right after. i'm still not pregnant?

You may be very soon: If a woman is young and healthy, she will likely get pregnant soon. Her body is designed to get pregnant and have babies... So it's just a matter of time. Be sure life is ready for a family (meaning getting married, settling down, having a secure job, etc...). Otherwise, it's time to buy lots of condoms, and ask the doctor about additional methods like birth control pills.