Brown spotting? Concerned

I am about 8 weeks pregnant with my second. For about a week or so I have been getting brown spotting when wiping on and off, not every time I wipe. Today I wore a light bad to see if there would be any and there was a little on it. Not really having any pain. Occasionally I get a slight cramp. Had ultrasound at 6 weeks and saw good heartbeat.

Should I be concerned about this?