Pregnant on the pill?

I was supposed to get my period on Aug. 26th and it has yet to come.

I’m on a combination birth control pills and I was about 20 hours late taking one pill on the second week and one pill on the third week. I had unprotected sex a couple times during those weeks.

I’ve taken 3 pregnancy test on different days and times of the day and they are all negative.

Yesterday (Aug. 28th), I was having such horrible uteral pain with cramping and I passed some clots with bloods. I’m having some discharge and more smaller clots today as well.

I’m nervous if I’m having a miscarriage or if that’s my period? Should I call my gynecologist? Could it be a chemical pregnancy? Should I start my next pack of birth control or wait?

Please help. Thank you!