Help!!!

Ariel
Help me please. My glow said that my most fertile day was August 21st. Fertile week was from 17th-23rd. Had sex the 18th, 21st and 22nd. Last period was July 27th-30th. Before that was June 17th-20th and before that was May 13th-17th. I thought this month would be the month. But yesterday I started bleeding!!! It's bright red blood looks like a period. But period isn't due till beginning of September and every app I check says the same thing. What is going on? Do I have a chance? Is this my period? How do I determine future fertile days now? Idk what to believe & I'm so disappointed:(