Hi, i had 2 days of light bleeding and today quite heavy, could it be a sign of implantation bleeding?

It is possible: It is possible but implantation bleeding is usually not heavy. If you think you may be pregnant please take a pregnancy test. They are most accurate 3 weeks after sexual activity or one week after a missed period. If you are having unprotected sex then please take a prenatal vitamin with folate (folic acid) daily to prevent birth defects.