So confused

Okay, so my cycle is usually anywhere from 28-30 days. I wasn't supposed to start my period until the 11th of this month. Instead, I started spotting brownish blood on the morning of the 4th. It was barely anything to even wear a pad honestly. Then the next day (the 5th), I started spotting brownish light pink blood, but yet again, only really truly notice it when I wiped. Then early morning of the 6th, I started actually bleeding and it was bright red blood mixed with dark red. It had clots like my normal period would be, but it just got heavier and heavier. It ended the next day. The 7th, that evening. So my question is, has anyone ever experienced anything like that before and what was it?