What causes me to bed wet?

You do not provide medical history and more details about your problem so it's difficult to figure out the etiology. You should read this link and see it it helps - https://www.beaumont.org/conditions/enuresis. Good luck!

There are 2 different types of bedwetting: primary (never had a dry night at least 6 months since birth); secondary (associated with neurological condition, e.g., cerebral palsy, neural tube defects, metabolic conditions, e.g., diabetes mellitus & insipidus, psychologic condition, e.g., polyuria-polydipsia. Primary enuresis is associated with strong family history.