An irrational fear could be Cynophobia - a fear of dogs
Steps to overcome the phobia might include CBT to understand and analyse your fear process.
Exposure therapy is useful in using small steps to decrease your fear over time through desensitisation
This could include starting with imagining a dog, then seeing pictures of one, progressing to holding a toy dog,
Watching real dogs from far away and eventually being able to be near and even touch a real dog