I had it at around 6 weeks, lasted a few days, dr said it can be normal but gave me a scan to check, and there was my lil bean all fine. She said it could be due to implantation bleeding and the bloods taken a while to come out. That being said ive had brown discharge for about a day once a week. Dr still says its fine, but to see her again if i have cramps along with it, or red blood. So chances are its absolutely normal. But get it checked so you can have peace of mind