Spotting during early pregnancy

Stacie
I'm about 4 weeks pregnant (just got my BFP on Saturday) well, today I noticed light, brown spotting after exercising. I've been exercising regularly since before this pregnancy. I never had spotting with my daughter and my last pregnancy ended in a miacarriage, so I'm not sure if I should be worried or not. 
Is brown spotting worrisome? Should I take a break from exercising?