Implantation bleeding or period.. what do you think?

I had unprotected sex on the first day of my ovulation period which was June 10th.. just 3 days later and up until yesterday I've been have pregnancy symptoms.. like nausea breast tenderness backaches headaches gassy going 2 the bathroom more and eating alot.. my cycle normally starts on the last day of the month.. but what i assume 2 be my cycle started 2day.. 3 days early.. the blood was light in color at first with a brown color.. but now it's gotten a little darker.. also the cramps have stopped but Im still having the nausea.. I've taken 2 pregnancy test (1 Sat. morning and 1 sun morning) they both were negative.. I was told that it could be 2 early.. considering the fact that i would only be like two weeks and some days along.. i went 2 the doctor 2 day and once again the urine test was negative.. so im i testing 2 early and i could be pregnant.. or is what i think my cycle is actually implantation bleedin.. or could it just be my period started early..and please honest answers..