get over my fear of flying

I’ve been flying since I was a baby, and was fine up until my early 20s. I don’t know why it hit me then, but for some reason I’ve gotten tense during the weeks building up to a flight. For someone who has successfully flown to places as far as Japan and Greece, it sucks to be dealing with this now. Since developing my fear, I’ve flown several times, but I want to get over the severe case of nerves I feel before and during so that I can learn to enjoy flying again.