Becoming “regular”

Hey everyone! The hubby and I are ready for baby #3 and have been trying since March. I was taking the Depo shot for Birth Control prior, my previous babe it took 6 months as well to conceive after coming off the depo then, too. This time I’m having a hard time because my cycle is SO irregular. What are some tips to get regulated again after the shot so we know our “prime time” more accurately