See a different dr who can do the b/w and run some tests! Second opinion will not hurt.
i think i asked before and oyu tod me 'no' that you hadn't had bloodwork done. i would demand this of them! if they didn't run all the test(s) possible to determine thier diagnosis, i wouldn't be satisfied. perhaps you were very early in pregnancy so they couldn't see anything (how far were you supposed to be), perhaps you are experiencing a m/c. have you passed any clot like materials? if you stomanch is hard and you are m/c, it may be your uterus contracting to get back to normal. at this point it is so hard to tell when you have so little answers/help from your doctors and tests.
How far along are you supposed to be? Did they tell you at what point they thing the baby passed? Perhaps it is not really a m/c....