Period talk

Hey guys, i’ve never posted before so i’m a bit nervous!

I started my period in 8th grade and it’s always been normal up until this summer (i graduates HS in may). I got on birth control for the very first time in July, i’m on Nexplanon. I got off my period the day i got the bar put in. and since then i haven’t bled at all. (the doctor said this would be normal)

So my boyfriend and i had sex 2 weeks ago today and last night i noticed i had discharge coming out. it was dark brown in color and today it has gotten lighter in color and is now kind of jelly like.

What do y’all think it is?? HELP!