My Periods are very irregular?

There's no way to tell from here what is causing the irregular periods. If you have lost a lot of weight recently, that can do it. You will need to see a doctor to figure out the cause. Dont' worry about premature menopause--that's quite rare and not the thing to first think of when you meet a 16 year old with irregular periods. You really do need to tell your father about it. It's part of being a parent that you help your kids with stuff like this.