Hello and welcome! I'd like to help you think about some ideas for figuring out what's going on with you and how to address it.
There's a few things that stood out to me in the information that you provided.
1. It sounds like you have an issue with setting and keeping appropriate "boundaries." "Forgive and forget," might sound like a person who is caring and compassionate, but it sounds like in your situation it's that people are walking on you and you are letting them get away with it. Therapy is a great way to learn what boundaries are, how to set them, the best way to practice, etc....but you could also buy a book on Boundaries. There's a bunch on Amazon. My favorite is Cloud and Townsend's "Boundaries", because it's so comprehensive but it's written from a Christian perspective, so some are not going to like all of the scriptural references.
2. Handling Stress: I'm wondering if your work and your personality style are a good match. For example, for a person who gets their energy from a lot of "alone" time (introvert) might struggle in a job that is based on constant people contact.
The Meyers Briggs is a good test for understanding your personality, how you approach problems, people etc. The real version (you have to pay) can be found here:
You can find some "knock off" versions if you google similar terms.
3. Repeated Mistakes: You are stuck somewhere. There's many, many reasons people get stuck--but if I had to generalize, it's from an unresolved issue from the past, most often childhood. Understanding that issue and working through it often gets people unstuck --therapy is really one of the best ways to do this, where you sit down, one on one with someone who help help you focus on pertinent things to figure out where you got stuck and what is keeping you there.
I hope this helps --please follow up on any topic, like if you want help as to where to look for a therapist or whatever you want.