i just wipes and noticed this discharge.

i start my period on thursday.

background: i am on birth control pills (have been for 2 years) and have not missed a pill. my boyfriend and i had sex like 3 times this month, each time he does not finish inside me. i read online about implantation bleeding so it’s kind of freaking me out a bit with the top of the toilet paper having that red line of blood. i also read that if i got implantation bleeding it would’ve been way earlier too. please help!