Brown discharge...anybody else?!

Hi girls! I need your help:

I am 8w and 5 days pregnant today and I have been having brownish discharge on and off since I was 6 weeks. My gynecologist says that if I don’t see bright red blood everything is fine...but I cannot help but worry every time I wipe or see something in my undies. It goes away for a couple of days and I think everything is over and then there it comes again. It has been a pretty light discharge but I feel like my uterus is very sore sometimes and sometimes I have pain even though I don’t have cramps, what could this be? Anybody having the same? My last pregnancy was a blighted ovum and I am so afraid to lose this one too...