OPK Question!

I went off Liletta IUD on Jan 7th and immediately had a light period, then nothing. My period was “due” on Feb 4th but never showed. I just started yesterday and holy shit AF is back with a vengeance (I haven’t had a period for the last two years).

I’m hoping this means my body is regulating itself, and I can actually start tracking things. My question is, should I start using an opk this month or wait until I get AF a second time to see if I’m regular?

I’m really confused with when to start opk and really just confused with the whole thing 🤷🏼‍♀️. I bought the ClearBlue one.

Thanks!!