At 6 weeks I had the same thing and went to the ER because it was stressing me out so badly. The nurse there told me that bleeding to worry about is actual blood that is flowing and soaking up more than 3 maxi pads in a day. Could have saved me about $200 if I had just waited to ask my OB but when you're worried it's hard to think more rationally. You're probably just fine.
Brown blood is old blood. Try not to worry, it us quite normal. I bled from week
6 to 16 of my pregnancy and my twins are 3 1/2 yrs old. Drink 80oz or more of water a day. It ciukd he your embryo implanting deeper, or from your rapidly growing uterus. Congrats!!!
I had the same thing with this pregnancy and it freaked me out a little because with my first I had nothing of the sort but it went away further into the pregnancy and my OB said all was well!
Its probably implantation spotting i wouldnt be concerned unless its severe blood and severe cramps