Slight brown spotting at 8 weeks? Should I worry?

There doesn't seem to be anything to worry about at the moment. There is no bright red blood, no heavy bleeding and no intense abdominal cramps which doesn't indicate anything to worry about at this stage. As you probably know, spotting is quite common in the early stages and sometimes continually and as long as the blood is brown (it signifies old blood) or pink and isn't bright red, heavy or accompanied with unusual amounts of pain, there's nothing to worry about.