Snot like discharge, help?!?

Lately I have been noticing a snot/not thick in consistency like discharge when I wipe and sometimes in my panties (I am female.) I'm on birth control and have been for about two years, I take it so that I only get periods a few times a year. I keep trying to remember if I've ever noticed a discharge like this before and I'm unsure.. I've always had discharge but this is just a little concerning. I just started a new pack of birth control probably a week or so ago, I missed a birth control pill the other day so I've been spotting some, so the color has ranged from clear, to pink to brown/dark red (old blood color.) I'm just wondering if this is normal? I had the discharge BEFORE I missed the pill, I haven't done anything differently lately, no change in medicines, diet, etc. I'm just extremely concerned and would appreciate any responses!