this stress must be horrible for you.
I had a couple of bleeds at the very start of my last pregnancy but not as heavy as you have described. Like the other ladies have said, I really think you should get a 2nd opinion because your ob only said where it 'wasn't' comming from, not where it WAS coming from or what was causing it YKWIM? My dates measured 2 weeks behind for both of my pregnancies as well and the lovely girls here on BB assured me it was quite normal cause I think my dates were according to my LMP, but the scan was by actual conception.
I hope you get some straightforward answers very soon!
Gool Luck!