Why do I have these phobias?

ok I have a big phobia. One phobia I have I guess is called entomophobia. I dont get it though I can see a roach and kill it nothing to it, but when I see more then one or in a bunch I’d like to say I start sweating screaming, I get dizzy my heart races an occationally pass out. I am kinda the same way with spiders and mice. Pretty much anything insect wise or rodent wise except flies. Also I have a fear of going anywhere whether its in the house or outside in the dark. Im ok if there are people around me I am not scared but when I am by myself I will make excuses to go outside. Then finally, I cant go out in the sun. I think it is because I got second degree burns a coup;e years ago and now going out in the sun is hard for me. Am I ok or do I need some sort of mental help?