So I am 26 years old and I have Endometriosis. I found that out after I had my IUD removed (This was back in May). After my IUD was removed I switched to the pill form of birth control. The only regular thing about my period is that it is irregular. If I miss a pill, I will always start my period the next day. I recently (within the last two weeks) ran out of pills and I couldn't refill them for three days. I never started my period nor did I ever have a sign that I was going to start my period. I took a pregnancy test and it came back negative so I started taking my pills again. According to my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period calendar</a> I am supposed to start my period on the 12th. Could I possibly be pregnant?