It can take up to 2 years for everything to return to normal - although obviously everyone is different. I was on Depo for 10 years, so was expecting it to take a long time. I had my final injection just before my wedding (as I was worried about the big day & honeymoon being spoilt by a period!!), and then went on the pill - as although we didn't want to TTC immediately, I knew we would within a couple of years and the pill wears off much faster. I stopped the pill after 18 months, and was pregnant after 2 months TTCing.