Period question, I need answers!

Abigail • Hey I'm Abby✌🏻️i like horror movies and sushi. Oh and I rock the ukulele.
Okay so I'm on the pill to regulate my period and to prevent pregnancy. Well the preventing pregnancy part is working great, but it's the regulating that's all messed up. My period will show up 2 weeks early, and while I'm thankful that I'm getting my period, it's just a little irritating that it's always early and never on the date at which it should be according to my birth control. Can someone please give me some answers as to why the hell this is happening?😣