Excessive periods after surgery

Hi everyone, I have been trying to look up information on my issue and not having much luck. Before surgery I was on the depo shot, and never got a period. Well..right after surgery I started my period, but figured that was normal because I have heard that. I had it for about a week and then it stopped, but came back 2 weeks later. (had surgery oct 30th 2006) I continued to have my period on and off every 2 weeks, and they were heavy. Then, since January I have had my period pretty much non-stop, with maybe a days break in between 2 of them. So I am pretty much bleeding heavy and all the time. ANy idea why this could be happening? I am still on the Depo shot as I was before, nothing has changed except for having LAP RNY surgery. I am going to ask my Dr when I see him Feb 27th, but wondered if anyone has experienced this or may know what is causing this. Im afraid Im gonna lose too much iron and become anemic. Thank you for any advice or thoughts! Shannon