Depo questions

I had one depo shot last fall. It was due in December but I decided to go off of bc. Generally in the past when I did depo my cycle went back to normal within a couple of months. This time, I didn't start bleeding until May, and had either heavy spotting or light periods every two weeks. I think I had my first "real" period two weeks ago, but started the weird heavy spotting mid cycle. It only lasted 2-3 days. My doctor says wait it out, but I think it's strange. Anyone experience this? Been ttc since January. I'm 33.