Period clotting TMI PICTURE

Hello, Last month, November 20th, I began spotting. I have fairly regular periods and it was the correct time of month. On the 26th I had sudden and severe symptoms. I felt nauseous, bad abdominal cramps, and really bad diarrhea. I laid down with a heating pad and then went to the bathroom again. When I took out my menstrual cup I had a VERY large clot. I took a pregnancy test right after and it was negative and all of my symptoms went away. I continued light bleeding for a couple days (normal span of my period). I was worried it could have been a miscarriage but did not think that was possible w a negative test. However I did take it in the afternoon and not morning. I am currently 3 days late (which has not normal) and pregnancy tests were positive. I was wondering if this could have something to do w the large clot from my last period or I am in fact pregnant. I cannot get into my OB until I am around 8 weeks. Thanks for any advice!