What contraception to use to avoid weight gain?

i am 28 years old and currently taking levlen ed a 30mg combined pill. since taking it i have gained weight that i cannot bugde i eat a healthy diet and do cardio workouts and yoga 5 times a week. i have body ysis scales and my fat level and what not does not change. I have had the same experience with implanon and depo along with constant bleeding and the works. i am extremely fertile - i fall pregnant at the mere mention of it!!! but my weight is now 66kg and i have maintained my weight at between 50 and 55 kgs all my life with no exercise - i have been lucky. my bmi is halfway through the overwight range and my fat percentage is over fat at over 30%. please no comments saying keep dieting, keep exercising cos i have been here before - it is unshiftable weight and it is really doing my head in and my depression is getting worse. What can i take that wont do this to me and what causes it - i thought it was the progestegen but there is no contraceptive that is eostrogen only? can any body out there help with any suggestions please???