am i having a miscarriage?

just over a month ago i had sex with protection, it was on my most fertile day. a few weeks after i started vomiting in the morning, i’d lost my sex drive, my boobs have shrunk and i am so emotional and i never am! i never took a test so i’m not sure if im pregnant.

today i woke up with my ‘period’ and the cramps are the worst they have ever been, my period is so heavy which is weird for me as it is the first day and the blood has quite a lot of clumps. do you think i am having a miscarriage? what should i do?