What Does Brownish Vaginal Discharge After Intercourse Indicate?

I've had unprotected sex twice with the same person in the past couple weeks after the first time I had a brown discharge for a couple days and then I only saw pinkish discharge when I wiped after the second time I have pinkish when I wipe and used a panty liner which I see a whitish yellowish discharge I don't smell fishy but it doesn't smell normal either I'm on the depo shot for almost a year and haven't had menses since the first depo shot. Also haven't had much of an appetite since first time we had unprotected sex