If you have brown blood, then you should take bed rest, at least don't walk around for so long.
When I had the first ultrasound I was 6w4d, I could only see the sac and was very scared. They told me to go in when I was 8w, but I was scared and didn't go until I was 9w. When it was 9w, I saw the baby and the heartbeat. (but I still lost the baby afterwards....:cry: )
Anyway, don't worry too much. I always worried when I was pregnant and it didn't help at all.