5 days late, heavy bleeding after spotting, no pain. is it a possible miscarriage or could i still be pregnant?

Yes to both: Yes you could still be pregnant - or you may have had a miscarriage. This will often correct itself- but i recommend you go see pcp.

Not sure: Generally with heavy bleeding the chances of pregnancy are small. Could be a miscarriage. The highest number of miscarriages occur within the first 12 weeks of pregnancy. Wait until the bleeding stops and take a hpt. If bleeding dies not subside, see your doctor.