can you have implantation bleeding 5 days after ovulation

Me and my partner had sex last night 3 hours later.. I went to the bathroom
 And there was pink blood mixed with ewcm on the tp.
Is this implantation bleeding?
It's gone today.
It only lasted a couple of hours if that.
When should I test if it is implantation?
Does this guarantee I'm pregnant if it's implanation
Thanks