possible miscarriage? blood clot?

i started birth control about 3 weeks ago and have been having what i thought was breakthrough bleeding. today i bled more of a medium flow, not on the placebo pills, and i saw this. i’m not sure what to do or think. i had protected sex about 3 weeks before starting the pill but mistakes can always happen. please be kind as i don’t have a lot of knowledge about fetal development and i’m not a professional. looking at pictures online of other early miscarriages they look like this also but i’m just upset regardless. kindness and insight is appreciated. i’ve never seen clots like this before during periods.