Why would I go months without a period then have it one month then go without it for months?

There are a number of possible reasons. Fluctuations in hormones due to age or health problems, conditions such as PCOS, use of some hormonal forms of birth control are just a few examples.

Have you spoken to your doctor about it?

Menopause?

Without knowing your age, other physical conditions, including weight and other health problems, a person can not even guess. There are many reasons, and you will need to discuss this with your doctor and have a exam