Hey,
The pill can definitely help regulate your period, that is the only reason I have it. I'm in a relationship with another girl so clearly contraception isnt top of my list
Some pills say that they can make you put on weight, but there are many options where that isnt an issue now.
As for your mom, you should just go and talk to her about it, woman to woman. Explain that your irregularity is starting to annoy you, and make you frustrated. I'm sure she'll understand. There are many benefits of the pill, so don't be afraid to talk to her