Hey.. Um.

I got the depo shot about a month ago, and I haven't had my period since. But the past few days I've been having a weird discharge; it's like a dark, almost brownish red color. It has an odd odor, but it isn't like OMG EW or really strong, it's just.. In that area. And the inside of my vaginal lips are really tender and sore, and almost as if they're itchy, but not. I haven't had sexual intercourse, or any sexual play in about a week and a half, and I was fine after that. And it's not any STD or anything like that. I only have one partner, and he only as me, and we've both been tested. But anyways, this has just been these past few days, and I'm really concerned and annoyed by the, well, tenderness and soreness whenever I sit down, or sometimes even walk. Any help would be greatly appreciated. Thanks(: