You may need to find a friendly
Talk about Murphy in evidence here!
I remember I had an acquired dog phobia for a while at preschool age, because I was chased and bitten painfully by a neighbour's evil miniature dachshund, and because he was so small, all the adults were laughing as the dog pursued me, and nobody realised my skin had been stripped off me...
With more appropriate follow-up from adults, I probably wouldn't have felt quite so on my own about it, and not gotten so scared of dogs in response. However, that was cured when I was 8 and the family got a dog, which started out as a little playful puppy and ended up as a large playful standard poodle who loved water!
One phobia I still have residually is that steep drops freak me out if I'm too close to them, especially man-made drops. I've desensitised myself over the years, for example, by walking on the Tree Top walk in the Valley Of The Giants, which is a swinging suspended metal walkway through the treetops of the giant Karris and Tingles near Walpole, Western Australia, with a mesh walkway you can see through!
I just kept going around and around on it, until the nausea and the rapid heart rate settled. Also for my first few laps I avoided looking through the flooring. When I got more advanced, I started looking through the flooring as well. All in all though, you can see that it's a phobia very closely related to sensible behaviour around potentially risky drops, and has survival value (as long as you keep your head).
One thing I can't do though, is climb things like the Gloucester Tree, which is just a spiral ladder around a tall tree.
I've tried, but I ended up going black before my eyes about 10m up, and then decided that although I'd never actually passed out before in my life, this didn't guarantee that I never would. Passing out at a height actually would result in going splat, and this was something not worth the risk - although I'd happily come back with a safety harness to prevent fatal consequences from sudden loss of consciousness. One thing I did do after that, though, it to go to Hollybank Treetop Adventures with Brett when we were in Tasmania, and this ended up being amazing fun, and since we were all in harnesses, no risk at all from passing out etc (and I didn't pass out, it was incredible!). Here's some Internet photos of the place:
I think a safe supported environment like that is excellent for desensitisation from excessive concerns!