period spotting help?

Hey guys! I'm supposed to get my period today, but 2 days ago I bled a little bit it was bright red like the beginning of a period and it had blood clots in the blood. But then I stopped bleeding and haven't bled since...any ideas as to what this is? My tummy aches a little bit like when I'm getting period cramps and I've been eating a lot more lately but other than that I've had no symptoms. Thanks!