I am looking for an adjective, similar to "holding a grudge"
Resentful:
- Full of, characterized by, or inclined to feel indignant ill will.
In contrast with the more technical options presented in most other answers, and yet also hinted at in a few of those same answers: consider bitter, the emotional state of someone experiencing the hardships you describe. I think it fits the bill pretty closely and is also well-suited for casual, contemporary conversation. It's succinct, relatable regardless of your vocabulary, and even a little poetic I'd say.