So confused!!😱

My period has been very irregular and it's hard for me to tell when I'm going to start my period cuz it's always different. My calendar says I was supposed to start the other day and I didn't so I logged and said I didn't start, so now it says I'm going to start it Saturday. Trying to track my periods and when I'm ovulating is really hard. I'm feeling stressed. I just Got off depo provara about a year ago and everything since I've been having a terrible time and constant mood swings and weird sick feelings.. any help please is appreciated so much! Thanks.