I Had Unprotected Sex On July 30th And I Started Bleeding On Aug. 6th It Was Somewhat Heavy Bleeding But Only Lasted 4 Days (My Period Normally Lasts 6-7 Days). Could This Be Implantation Bleeding?, Could I Be Pregnant?

I Have Two Other Children But I Don't Really Remember Ever Bleeding Wih Them..

Can Implantation Bleeding Be Heavy And Last As Long As 4 Days?