I didn't have my period so I took plan b pills on the first day it's delayed, hoping It would still prevent pregnancy if ever. Five days later, i have light bleeding. Is this the effect of the plan b pill I took or is this implantation bleeding? Weeks before my period is due, my bf and I only practiced withdrawal method and my sleeping patterns changed and had some stressful days. Is this the reason my period didn't come or because I might be pregnant?