weird discharge

Okay. I'm gonna start by saying I'm so sorry for the grossness and detailing to this. I just don't know how else to ask except being detailed. So I'm on birth control. I'm on Erin (progestin only) and I started it back in October. And I hadn't had my period since then. Until this past week. And it was a normal period. But now that my period is over I have weird nasty discharge. And it smells so bad. I don't know how else to explain it except it smells like feces. And please keep in mind I'm a very clean person. I take care of my body.  So I'm going to make an appt with my OB. But I'm kinda freaking out about this. It's never happened before. Please help and again I'm so sorry for the nastyness. Thank you!