Weight dysfunction is either the result of over/under eating. That is choice and may even be a sin if it leads to poor health.

However, most weight problems are not by choice but are either a metabolic disorder or an eating disorder. both are a medical and not A morality issue.

See a doctor, there is hope and both are treatable.

My Du3as are for you dear Ukhti, may Allah(swt) grant you the strength and ability to seek the help you need.