Help? Not really trying to get pregnant!

So I've had sex 4 times unprotected this month, 3 during predicted fertile days and 1 one right after. My man had really watery sperm is that normal? And I'm 6 dpo and extremely crampy sore boobs and constipated. Which usually happens when i am pregnant but I took a test it said negative I think it's too early. Help??? Also not having discharge like i normally do..