One can definitely have a fear of emotions of various sorts, esp. strong ones. (I never actually think of it as a phobia, just fear, not sure why.)
Fear of strong emotions that feel overwhelming is really common if you search around on this site and elsewhere for complex trauma from childhood; childhood abuse often goes along with the child having no supportive adults around to teach safe experiencing and internal processing of strong emotions. The adults may even be the cause of most of the strong negative emotions for the kid; with no help available, for survival, kids can learn to squash the emotions... except the emotions are still sort of there since I don't think we control that part of our brains, the emotions are just walled off from consciousness in various ways for different people.
Learning to regulate emotions is a big part of recovery, and first we have to feel safer with the emotions in various ways, learning healthier coping methods than just squashing them into our muscle problems (for instance) and so on.
The strong emotions can also have led to more abuse for some kids, so it can be directly related to danger that way too.
We can definitely learn healthy emotional regulation skills as adults though!!! It's very worthwhile, in my opinion. Life becomes amazingly richer.