Hi I Have A Question I Had My Periods Approx

Hi I have a question I had my periods approx to 20 days before and right after that when My period were ending I had unsafe sex and since last 3 4 days I have severe stomach cramps today all of a sudden I am bleeding and it might be normal period as well but I was thinking that is there any possibility that this is not a normal period and this is a miscarriage I tried to see what's the difference between a miscarriage and the normal period and I think it is a normal period but my question is is it possible that this is a miscarriage the cramps are very much painful and it's just been 18 to 20 days so the question might be stupid but please answer my age is 32 years and I have hypo thyroid and hypertension thanks