Out of wack periods? Or something much worse?

So now I'm going on year 3 of having ridiculously irregular periods. Irregular as in bleeding really heavily for weeks - even sometimes months- at a time. My husband and I do want kids and this is why I'm so concerned at this point. My cycle is out of wack and the days are NEVER the same. For example.. just for the past few months I have been bleeding from Feb. 16-March 8. March 25-april 3. and now april 10-present. SOMEONE PLEASE HELP. I have seen every gyno there is to see and no one can help me. They put me on BC but before that all I had was a lot of constant bleeding ad clotting. since I had been taking the BC I get 2 periods a month, on average (unless I bleed the entire month) and I just don't know what to do anymore -stopped taking the BC in october of '09. Now Two days ago I just figured I was ovulating and thats why I was spotting and cramping so bad. Then yesterday It went away. it was light pink/brownish in color and only showed up when I wiped. and now I wake up and it's full out dark bleeding. No clotting as of yet but I usually don't that much anymore. Just bleed all the time. I've noticed that when I drink alcohol I tend to get my period as well.. or it definately helps to f**k up my body somewhere down there. I have been taking women's one-a-day prenatal vitamins in hopes of helping with my problem somehow, but to be honest this has been going on so long that I'm just about to give up with this whole thing all together (even though I don't want to)... any questions you have I can answer in hopes of geting rid of this horrid problem. Anyone just please help. I feel so useless to my husband for not being able to ever give him the family he so badly wants and it's tearing me apart.