Drought

I haven’t gotten my period in about a year and a half, this has happened once before. I had it and then went straight back into not happening. My periods before this started happening were regular af and then suddenly it just stopped. i think not taking my birth control the right way might have something to do with it but idk two years with out it is kind of long to still be dealing with side effects. also i’m 1000% sure i’m not pregnant. please help me figure out what’s happening!