Exercise, sleep and nutrition can always be improved.

Also get your hormone levels tested. I had cyclic depression from 15 through 25 and HRT has been a life saver. It becomes more noticeable at your age.

Everyone is different, but for me personally, a needle in the ass once per week is 100x better than depression, and it becomes something you have to live with, like brushing your teeth. Standard doses of 100mg/week are anarchaic though, look for 200mg/week and don't settle for the topical gels.