Foamy blood?! 😰 TMI but please help.

I finished my period on March 3rd and wednesday afternoon i suddenly felt very wet down there.. I went to the bathroom and the whole crotch of my underwear was brownish red. I was supposed to get my depo shot again in August of 2016 but i got married and wanted to regulate so we could try for a baby. This last period was only the third I've had but now im a little concerned. I was always told red/brown discharge was just old blood leaving the body.. But there was so much. This morning i woke up and the discharge is now a strange light red color and appears to be foamy. SOMEONE PLEASE TELL ME THIS ISN'T SOMETHING HORRIBLE.