I'm 17 Weeks Pregnant, Have Had A Threatened Miscarriage, Two

I'm 17 weeks pregnant, have had a threatened miscarriage, two prior miscarriages, then two full term pregnancies, but this time felt no baby movements, even though with my first two kids i felt them at 13-14 weeks continuously.
I just threw up (which is out of character becuasse i haven't had morning sickness at all) and it's completely dark brown. I have constant stomach pains and am not sure what to do.