Can you have a miscarriage and mistake it..

Can you have a miscarriage and mistake it as a heavy, painful period? (Last normal 6 days too?)

Every now and then I would get extremely late, heavy and VERY painful periods; ones where I had horrid blood clots that were bigger than a quarter and lots of them.

I've used the withdrawal method for almost 6 years too and always have sex on my fertile days but he pulls out.

Can a woman mistake this as her period? Do miscarriages last over 5 days? Are they heavy the whole way through or can they start heavy and end light like a period?