For The Past Two Months I've Had A Light Brownish,

For the past two months I've had a light brownish, foul smelling discharge. I have felt great other than that. Also after sex, I would see a dark reddish/ brown discharge on the bed. Made an appointment with my gyno for this week. Went to the bathroom and noticed a tampon in the toilet. It must've been in a out two months. Could this be the reason for the discharge? I plan on keeping my gyno appointment. What should I do in the meantime. It's been a few hours since the tampon feel out, but I'm still noticing a bit of discharge/order. How long can I expect this?