4 weeks 4 days and scared

Hi all, feeling a bit scared and looking for some reassurance!
I had a miscarriage at 10 weeks 4 days in August, and got my BFP on Boxing Day.
Been feeling pretty crappy and boobs are sore. But today I've passed a little brown bloody discharge and now scared stiff that it's going to happen again.
I know that some light bleeding is normal, just trying to calm myself down and rationalise it. Anyone been in the same situation? 
Thank you