"i started the shot when i was 17 about to be 18. i am now 20 about to be 21. very effective at preventing pregnancy. however, i have terrible mood swings, migraines, and weight gain. when i started taking depo i was the healthiest i have ever been. slowly but surely i put on the pounds and my depression became unbearable! the first year i didn&#039;t gain much, maybe ten pounds and went from a size 4 to a size 6. i weighed 135, now i weigh about 170. it&#039;s horrendous! i just switched birth control yesterday, so i hope it treats me better than depo provera!"