I can relate. The worst part is wondering how bad can it get? I've been flying for 30 years and still had the crap scared out of me flying out of Sedona last year.
The few things I've learned that help;
- Your local conditions need to be understood. Talk to local pilots about their experience.
- Understand the weather. Get the weather briefing and pay attention to winds aloft at your altitude. Take forecast turbulence as gospel until you get more comfortable (they're not). Check the pireps for reports at your planned altitude (also a poor source as few pilots report it). Taking off with a good understanding of the weather can give you a clue as to how bad, or not, the turbulence will be. Also understanding the type of turbulence can give you a clue how bad it might get. Thermal turbulence from the ground heating up only gets so bad, rarely an issue. Climbing over a 3000 foot ridge on a warm windy day can give you a very good jolt and altitude variation, but it is short-lived. Flying over taller mountains on a windy day... yeah, people have died. Turbulence from low cumulous clouds, without high winds at your altitude, can be very uncomfortable, but again, it only gets so bad and not likely to cause an upset. Flying near thunderstorms....I'm sure you've heard the cautions. The takeaway is having an understanding of the type of turbulence you may face before you take off can help alleviate your fears.
- Set personal minimums. Mine are forecast for moderate low level turbulence, coincident with winds of 30 knots or greater at my planned altitude. Then follow your minimums unless you are specifically testing yourself that day.
- Actively control the plane in turbulence. This has the added benefit of focusing your attention, rather than worrying about it (at least a little). What I mean by "actively controlling" is, keep solid pressure on the rudder pedals when flying straight (or at all times), focus on maintaining altitude and airspeed. Make gentle corrections with ailerons as the wings bounce up and down. In other words don't just hang on for the ride. Not saying you can't just hang on for the ride allowing airspeed and altitude to vary - just that you will feel more in control, and hopefully less fearful, when you are actively controlling the plane.
- Don't take passengers when you expect turbulence. Your fear will affect them as well.
The more experience you get this less your fear will be.