I didn’t include all of your long letter because the most important part of it involves your feelings. It sounds to me like you may have been suffering from dysthymia for some time. Dysthymia is a mood disorder where the individual is chronically depressed but at a lower intensity than in a full blown depression. As you report, it can go on for years and it can make life feel endlessly gray. I don’t know if your negative experiences with the former boyfriend are at the root of it. It may be that you would feel this way even if you’d never met him. He gave you reason to be angry and sad but it’s possible he only worsened an ongoing condition. As far as the job: It’s just true that wherever you go, there you will be. Changing the job won’t change your mood. Changing location won’t either. If the man you are with is a good guy, leaving the relationship also isn’t likely to help.
Instead, you need to see a mental health counselor. Bring your letter with you. You wrote an eloquent description of what you’ve experienced and felt. Your counselor will be able to hear more details and will be able to make a more sophisticated assessment. The two of you will then discuss treatment options. Some medication may be helpful to lift your mood a little so you will have the energy and interest to take better care of yourself and to take better care of your family. Some therapy will give you both some much-needed support and some practical ways to manage your gray moods.
You made an important first step in writing. Please follow through and get the help you need.
I wish you well.