Ob-Gyn questions? Ask a gynecologist online.
This is Dr. David
some birth control pills can cause more side effects than others.
you might need another brand of birth control pill or a lower level pill like LoLoestrin
you might benefit from regular exercise and consulting a nutritionist to help you count your calories to see if cutting down your calories can help you stop your weight gain
you should get your thyroid hormone levels checked as well. low thyroid hormone levels can cause fatigue and weight gain.
weight gain can cause more estrogen in your system and can cause low libido
at age 49, you most likely are having decline of your estrogen levels or early menopause causing weight gain and low libido.
you might eventually want to go on hormone replacement therapy and after menopause you won't need to be on the pill if your ovaries are not producing eggs anymore.
you might have to go off of the pill to get your estrogen and FSH and LH levels checked to see where in the menopause process you are at. you might be early in menopause
let me know if you have questions.