My period came on the expected day. it was fairly heavy the first day with clots but turned very light the next day. could that be implantation bleedi?

Unlikely--bleeding: at time of implantation isn't as common as many people think and it's very light, almost like spotting. Usually it occurs a few days before the period is due. if, however, you're wondering if you're pregnant, a pregnancy test is more reliable than symptoms such as spotting, nausea, breast tenderness and the like. Dr. Anne.