Ovulation testing after irregular AF

Jenny • I have an angel from December 2013, a baby boy born December 2014 and now tcc for a sister or brother after the sum!!! ♡
I ordered my ovulation tests for this months. I started AF today after day 46. Dr prescribed me pregesterone 200 mg to start AF. How would I know when to start my ovulation tests after this AF? Hoping this is my month (march)!!!