maybe a miscarriage

so i recently had sex and it’s been about 3 weeks since then and i got what i thought to be my period but there’s been large things that look like blood clots coming out and before that i had brownish blood, i don’t know what it is and i can’t go to the hospital for it. my breasts were tender and that’s never happened in all the years of getting my period. please help as idk wtf to do 😭