I would go see a Dr. JUST to be sure.
I had a gush of blood at around 5wks, just once. The next day it was thick brown blood that only came out on TP after wiping. And when having sex. It lasted from Jan 20 til just about a week ago.
Went for an u/s that day (jan 19th) and the little bean was there heart beating away. Had another u/s yesterday and I'm 9wks 1 day little babe is kicking and flipping away :)
It's not normal in all cases I had brown spotting with my first pregnancy and I miscarried so I always suggest to have your doctor check you out and decide if it is normal or not what's normal for one woman is not for another it's always better to be safe than sorry
Being that early in your pregnancy it could just be some left over period blood. I did the same thing and my doc told me to expect it cuz he could see the blood on the ultrasound. Dont worry. But if you start having blood and strong cramps make sure to get to the doc asap!