milk white and white jelly period, and a day after i have dark brown discharge

HI,

 i had my period 2 weeks ago, after that i started having milk white and white jelly comming out, a day aafter i have dark brown discharge comming out, did do a pregnancy test it said negative, i have allot of tenderness on my breast,nauses and lite stomic paint and a headdache that doesnt go away.

 Please help me in telling me what to do.

Thanx