Period lengths keep changing after stopping pill

Alice
Please help!? 
I came off the contraceptive pill in june. 
Had withdrawl bleed then first period a week later. 
Then another 32 days until next period. 
Periods used to be more regular than this before pill. 
Last month was 36 days and im currently on day 34! 
I am ovulating as taking opks!! 
But not getting pregnant 
Please help, any advice appreciated x