help please!

About two months ago I decided to get on birth control pills. Literally took them for three days and stopped. Well didn't get my period until 6 weeks later. If you'd even call it a period I was spotting only one time in the morning for three days straight. I took a pregnancy test because things felt off. Negative. Okay so fast forward to now and according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I'm three days late. What is going on!? I'm so confused. Should those three BC pills still be affecting my period now. Also, not sure if this has anything to do with anything but four months ago I gave birth to my daughter. I did not breastfeed however. I only bled for around 2 weeks after having her and shortly after that I got a real period.