I've taken my birth control pill only for 3 weeks now and my period is scheduled to be in 5 days according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a>. The other day I noticed that instead of clear, white discharge, my underwear was victim of dark red/brownish black old blood that I'm assuming came from my last period. I did not have this blood after my last period so I'm just wondering if this is a side effect of the birth control I'm taking? I'm 17 and I've been taking it at the same time every night. Does anyone else experience this?