I had one. It was alarming at the time but worked out fine.
2nd pregnancy and I bled at about 6+3. I went to EPU and they did internal scan and we saw the heartbeat (I am high risk of eptopic too so they were checking for that.)
I then bled like a very heavy period for hours at 7+2, I couldn't stop bleeding so was sent to the hospital in the middle of the night to check why I was bleeding so much. TMI but I had put a piece of kitchen roll into my knickers and there were huge finger length clots in the blood. I bagged this as advised and took it with me.
Saw a lovely, lovely, consultant who looked through the contents and said this is just blood, nothing to indicate a miscarriage but on the other hand, the bleeding is not good. Luckily I had stopped bleeding by then so was sent home on bed rest and to return in 2 days as an internal scan is hard when you are bleeding. I had a 2 year old. Dh worked from home.
Returned, was told I had a large (over 50% of the size of my sac) chorionic haematoma. I was not to do ANYTHING. Literally bed rest, no lifting, no walking, no housework, nothing, no sex and no orgasms either!
I think it was due to the size of the haematoma, they didn't want it dislodged by any means, as it was probably continuing to grow.
I did this, Dh and Ds were amazing in this time. I returned at 20 weeks for my normal scan and I was told it was now fine. Ds2 is now 14 years old.
So rest, don't lift, don't walk anywhere further than you have to. I have done a lot of research into it for both the UK and US sites.
Brown blood is old blood that has come out. Bright red blood would be the worry. I know this is terrifying.