Hi lybrate-user! the best way to know whether it's pregnancy
or implantation bleed is to test for pregnancy. You can do a pregnancy test at home using the kits available in market over the counter. If you still have doubt then a blood test B Hcg
or an ultrasound
can be done to be sure. I think you should try a urine pregnancy test at home first and if it's negative you can relax.