brown discharge 7 weeks pregnant

okay so just a little back story...I have had 4 miscarriages the last was 2-8-18 and today I should be 7 weeks 1 day pregnant. my doctor has already seen me three times. I was told that I would miscarry this baby as well. they did my 1st sono to get a date since I got pregnant before my 1st period after the miscarriage. 1st sono said I was 5 weeks. everything looked good. went back again for another sono because I couldn't bring myself to get the d&c; unless I really knew....well I shoukd have been 6 weeks 4 days BUT the sono was measuring 6 weeks 2 days. doctors were happy with the progress and said that I have to go back when I'm 7 weeks 3 days based off of the last sono which I go Wednesday. I'm freaking out because last night unna be some weird discharge and then this morning when I wiped the toilet paper had a tint to it...no discharge just a brown/dark res tint. do I call the doctor or just wait two more days for my next sono?