Help! Im desperate

Hi everyone! Im desperately in need of help! Im 4 days late for my period, yes I have had sex but everytime me and my boyfriend have had sex, we used a condom. I've taken 3 tests that came back negative to being pregnant but I've been having all these different symptoms like feeling sick, my appetites grown, I've been really emotional, my breasts are tender, my back is sore and I need to pee like all the time! I dont know wether to trust the tests or not. I mean, are they 100%? What should I do?