Is this implantation?

I had sex on Friday (it’s Monday now) yesterday morning I felt dizzy and today my head feels sort of hot/heavy it’s only just happened. I know it’s too early to test or probably to early for anything but do you think this could be a sign of implantation happening? I’m not sure when I ovulate as I’m still breastfeeding my 1 year old and my periods are very irregular I’ve only had about 3 of them. I also feel the tiniest bit nauseous not majorly.

With my first I found out I was pregnant due to nearly fainting after a shower and my second I felt a bit sick after a bit of wine.

Could this be implantation or do you think it’s nothing?