Hello, I'd like to help you with your question.
It sounds like you might be depressed. You have some of the symptoms including low feelings, black thoughts and deep anguish. That describes either depression or grief. Add
to those symptoms the feelings you describe of wanting to jump off the tube which could be a way to express that you are very unhappy with your life as it is now.
You mentioned that you have had a hectic several years and that you have experienced relationship problems recently. That may explain why you are feeling as you do now. If you have gone through any loss, you may be experiencing feelings of grief and/or depression. People can grieve anything from the loss of someone to the loss of a home or job, even a pet. And sometimes you will find yourself stuck in the depression phase of grief, where it is possible to feel as you do now.
You can overcome these symptoms. One of the first steps to take is to seek therapy. A therapist can do an evaluation for you to determine exactly what your diagnosis might be. Once you know what is going on, it is much easier to treat it. Talking to a therapist can help. But you also can share with friends and family. There is healing in sharing your feelings and letting others know you are struggling.
Also, consider support groups, either on line or in person. People who are experiencing the same symptoms as you are can offer invaluable support, ideas and companionship to help you feel better. Also, working on your depression at home can supplement your therapy or other treatment. Here are resources to help you get started:
Once you are able to reach out, you will start to feel better. Let others support you and offer help. You do not have to do this alone.
I hope this has helped you,