Could i be pregnant? PLZ ANSWER. driving me crazy..

Patient: I had unprotected sex with this guy a lot and one of the times he thought he came in me. its been 6 weeks now and since then alot of watery discharge has came out, frequent headaches, stomach cramps, back aches, mood swings, hot flashes, i hve to pee all the time, my stomach has been bloating at night, ive been eating alot and all i ever want to do is sleep. but i took four pregnancy test about 4 weeks after and they all came out negative. also i usually gave very heavy periods and it came a day early and was very light started off brown and turned light pink then to its normal color. im only 15 so im freaking out.. could this all be in my head cause its all ive been thinking about and thats why im having all of these symptoms or could i be pregnant? also ive never had most of these as PMS symptoms and its been like this for 4 weeks so im pretty sure its not my period coming.