I agree with the others. It doesn't matter where or what you're in. The water won't protect you or act as any birth control because the penis is inside you. Pre-ejaculation is also always present when a male is aroused----it makes no difference how long it takes for him to actually ejaculate. Wait 2 weeks and take a pregnancy test with first morning urine. Use condoms and birth control AT ALL TIMES if you don't want to become pregnant. The pull out method is also not birth control and will NOT protect you against pregnancy.
Any time you have unprotected sex you risk the chance of getting pregnant. If your period is late, take a home pregnancy test. Then use this as a learning lesson to always use protection.
Pre ejaculate (or as you referred to it pre-***) is present during most of the time. it can get your pregnant and if you were ovulating when this occurred you could be pregnant.
Wait two weeks from the last sexual encounter and take an hpt.