Unprotected Sex Advice Please

Hi!

I’m kind of nervous and could use some advice. My period is always pretty irregular but I had somewhat sex (it was in the water and for five seconds and I don’t even think he finished??) last month the day after my period ended. Is it possible to get pregnant the day after your period?

I’m three days late but I also am recovering from coronavirus so I’m assuming the stress from that is playing a factor. I also typically am irregular and I think I’m just paranoid.

Could use any advice thanks!