When will my cycle be normal?????

I went on birth control last May and went off it this February. Prior to BC my cycle was very regular (every 28 days) since I've been off BC my cycle is messed up. 31 days, 24 days, 21 days.. I have no clue when I ovulate or when my period is coming and it is soooo annoying. What should I do????? I ant to have kids soon but how i'll I ever know when to try if I have no clue when I ovulate and what my cycle will be like each month??? When will it go back to normal?