Will Bleeding Of Spots Red And Brown , Cramping A Matter Of Concern?

I am guessing about how far along I am approx 6 weeks? i have yet to have an ultrasound but have been to the doctor 3 times for bleeding they have taken my blood each time.. The first time they took my blood i went in because of bleeding and cramping. My hgc level was at 37% and they were guessing i was miscarrying. i went in two days later and they were over 200% and went in another 48 hours later they were over 700% (this was on wednesday the 5th). I have continued to bleed not much, more or so spotting to light bleeding but enough to wear a panty liner, everyday for at least a week now most of the time brown and maybe 25% of the time its red red. Doctor just tells me to drink plenty of fluids no activites or intercourse. Today still spotting and red again, I'm still worried but wonder if i should even call my doctor cause they would probably tell me the same thing to just drink water and relax. I have an appointment for my first ultrasound tomorrow, im fearing the worst. Any suggestions or comfort for me?