irregular periods after baby

I had my baby girl at the beginning of March. My next 2 periods after came as they were supposed too, but then I didn't have one in June and finally got it 17 days late on July 14th. My cycle is usually only 33 days but that one lasted 50 days. Now I'm currently on cycle day 53 and no sign of it showing up. I took a test a few weeks ago but it was negative. Could it just be too soon to test? I'm really hoping were pregnant with our rainbow.