I know exactly how you feel. I am the same way in that I really, really want stability and predicatability. I started at State Farm right out of college and planned to never leave strictly because of how stable it was. When all of this upheaval started it was very stressful on me. It took a lot of emotional effort, but I finally took the plunge and started interviewing. I started small with just prepping for interviews. I knew that the worst that could happen is that I learn new things and get better at my job.
I ended up with a job through an old high school friend I had not talked to in 10 years. I had to decide to take risks knowing that I would grow with each new uncertain circumstance I dealt with.
I also have the privelage of being married to the most amazing woman. I know that she and I can get through anything together. If you have a life partner, talk to him/her a lot. I always found that verbalizing my fears and anxieties helped put them in perspective.
Anyways, that’s a lot of rambling hopefully some of which was beneficial. Remember that nothing is certain in life. Figure out how to accept and embrace that fact. You will never get over your fears until you put yourself in situations where you are forced to deal with them. Good luck!