What Causes Whitish Vaginal Discharge With Bad Odor Post Intercourse?

I ve been having a gray/white discharge coming out of my vigania. It started about seven months ago when I had sex. The discharge doesn t have a fishy smell to it. It actually smells like feces if that makes any scenes. The odor usually gets worse through out the day and my vigania itches really bad and also burn. I haven t went to the doctor for a check I told my mom about it she thought it was an yeast infection and told me to buy monistat. It didn t work at all after a week of using it the smelly discharge came back I m so irritated that I have no one to talk to so this is my last solution. I really want my mom to help but I don t stay with her and I m not under her insurance. Oh I ve also been having minor headaches and soreness in my muscles I don t know if that have anything to do with it or I m just stressing over the situation