i agree...therapy will help you vent your feelings and assist you with ways to cope with those negative feelings and hurt. i found i needed to have the courage to look at things that bother me. i learned how to understand myself and get on with a new way of coping. the feelings you have toward strangers sound like it's transferring those pent up feelings to ppl you don't even know. i'm sure that makes you even more unhappy. they may already feel bad about their own situation.
so yes i'd seek out help so you can feel better about yourself and also learn new ways of thinking. sorry you feel so isolated but know you can feel better too. it just takes time to sort out who you really think harmed you and ways to deal with it constructively.