First day of period-like bleeding at 6 weeks

Diana • TTC #1 successful May 2016, thanks to Glow
I wasn't wearing a pad or liner at the time so don't know amount but more than just spitting....like first day of period. Some cramping too, but not much worse than what I had been having before. I'm feeling worried it's a miscarriage. Would testing with an HPT show a lighter line in that case? The last time I tested, test line was same shade as control line but that was about a week ago.