first post

This is my first post here and hope I can get some insight. So, I am little bit confused of when I should mark my first day of period. I have regular,monthly cycles, with mostly 6 days. According to glow I was suppose to have my period on Wednesday, but they didn't happen. I was still experiencing a lot of cramps,stomach/back cramps/pain, sore breast, etc. Thursday I didn't get it in the morning,but still experiencing cramps and pain. Then around 7:30pm Thursday I went to the bathroom and there was blood in my underwear, not a lot just spots. I wiped and it was brown.  I wore a pad and it was just little discharge which I notice is all brown. This morning the discharge was more and its red. Should I mark today as my first day of cycle?

Thank you