Depo shot

Iv been off depo for almost a year now on dec 23 2015 iv had my period all year and on the 16 of October I missed my period it's been 6 days still no period but white stuff comes out my vagina and I get light cramps but no period I feel moody nauseous and have the feeling of throwing up but can't I took three pregnancy tests but they were BFN idk what's going on I need advice