Can someone shed some light?

Ok. So here’s my story, it’s not too long.

So I just stopped breastfeeding my babes around the end of January.

Feb 8th my period shows up. Awesome. Second one since he’s been born.

So I start using opk because we want another baby..

February I didn’t ovulate.

Fast forward to March March 28th I finally got my positive!

So March 28th, 29th 30th and 31st we baby danced! Whoop.

Now what day would I start my “dpo” do I start on the 28th? Or would it be safe to say April 1st?

I have NO idea when my period is due.. as my last one was in feb.

At what point would I be safe to test? I was thinking the 14th? Reading up on it sometimes implantation doesn’t happen until 7 to 9 dpo.

I’ve just had mild dull cramping on/off for the last day or so.

Basically thinking every time I go pee I’m gonna see my period but nothing yet.!