I can't tell you not to be afraid, but you do have to push past your fear.
When I first got my gelding 16 yrs ago, he was a certified, bonafied crow hopper. Whenever I asked him to lope, he would take about 4 strides, then put his head down and start hopping. He would bounce me off Every time, lol.
So I would get up off the ground, catch his rein, and make myself get back on. I would just wait until my legs stopped shaking, then I would focus on Breathing. I wouldnt necessarily ask him to lope again right away, but we would certainly pick up a lot of trotting.
My advantage I think was that I at least had some knowledge of Why my horse was crow hopping. The horse was young and Very green, and his previous owner would literally just smack him on the ass to get him to race down the dirt (stone) roads. So I figured the horse equated running with over excitement and fear. I had to convince him that even though we may be moving fast, we still had to be mentally calm and relaxed.
So I would just talk to him calmly as we did our transitions from walk to trot to lope, kept up a steady flow of soothing words, and made sure I did not tense up my body or legs, even if my heart was starting to race.
And ya know what? The soothing tone of voice kept ME calm as well, and I was able to relay that to the horse.
So it would be helpful for you to find out why your horse is misbehaving. I think I was lucky, my horse is generally very good natured, and never had any barn/buddy sour issues which I think would be harder to fix.
If he is crowhopping just cause he is being a jerk and doesnt want to work, you are going to have to get tough with him.