It doesn't sound like pregnancy per se. Sometimes the kind of symptom you are talking about comes from a forgotten tampon. Is there any possibility you forgot to take the last one out after your last period?
Hm, a strong odor to me always makes me think that you should get checked for a bacterial infection. That's hard right now to do. But any time our blood mixes with discharge, it gives it a funky color. It can be pink if bright red mixes with white discharge, tan if brown(old blood) mixes with white discharge, etc. So, you sound to have old blood making it's way out. If it continues, it's no longer discharge and would be considered spotting. That can happen for lots of reasons.
Good questions from Annie. And then also, when is the last pap smear you had?