My period is usually 4-5 days long. In December my period was on the 21/12/2011.Had unprotected sex on the 31 December. On the 2 Jan I went to the loo and wiped and there was this light brownish discharge, which happened just that once. I had unprotected sex again on the 14 of January. My period started on the 23 but I did not wear a tampon at all, just pantyliners (was clean), there were hardly any blood, just when I wiped, it lasted from the 23rd till the 26 January .the 30 January am still having the bloated feeling, constipation and sometimes nausea and very emotional. I did do a test on the 28 Jan but it was negative,went to the doctor on the 1st of feb, another unrine test and that was also negative. My breasts are still really sore and sensitive, I get the odd period pain type cramps, bloated, nausea at times and slight headaches as well as tiredness. Any advice what could be wrong.