i was 2 weeks late for my period now ive had a big blood clot does this mean ive had a miscariage

It's possible, especially if your cycles have been very regular. You'd have to have had a HPT or blood test to be sure though. If your bleeding gets really severe or if you're in a lot of pain, go to the Dr right away to get checked out. If your cycles still remain odd, it could be a hormonal issue, but if they go back to very regular there's a good chance it could have been a pregnancy.