Can I be pregnant 100% sure?

So my period end about a week ago and I started bleeding again today but between this time, my boyfriend and I kind of had sex but it’s really wasn’t sex because we didn’t have intercourse but his penis might of accidentally touch me down there so the next day I took a plan b pill just instead. I’m not sure if my bleeding today is a implant bleeding or could be a side of effect of the plan b. Advice please?