Hi Warwick,
I fully understand what you are saying. There is a tremendous amount of stress in just being alive these days. Top that off with all the things that Fibro brings into the picture and it is deeply challenging.
Many people equate their sense of self-worth to what they can do and accomplish. This is a Western society value system that is deeply embedded in most people who live in countries in the west. When you find yourself no longer able to fulfill this requirement, it leads inevitably to depression ans many of us experience that, so don't feel alone. I struggle with that all the time, but have gotten better at handling it and you can too.
Diazapam is basically a sedative, so it may very well be making your depression worse. I would suggest you try doing without it, if your doctor approves. I don't know the other meds you are taking. I do know the effectiveness of medical cannabis, though, and I highly recommend that you give it a try. It has helped many people a great deal and I am one of them. It is very important that you use a tincture, or an edible of some form, and don't smoke it because the smoke is every bit as bad for you as cigarettes. It's also vital that you start with the tiniest dosage possible and work up very slowly to find what works for you.
work with your doctor to try different medications and try not to take too many of them if possible. Experiment. Be your own advocate.
Depression and feeling worthless have been my companions for many years, even before I got Fibro, and of course got worse. I have worked very hard to learn how to manage that. It's hard. Not everyone can do it, and don't let anyone tell you that "all you have to do is choose to be happy" because that's B.S. If it were that easy everyone would be happy. It doesn't happen overnight or quickly or 100%, but you can probably learn to lessen its effects in your life.
Here is what I have done and still do: Eat as healthy as I can. Get enough sleep even if it means I can't do other things I would like to do. Get some kind of exercise every single day. Not always a lot, some days I go for a long hike or dance for two hours; other days the amount I do is pathetic, but I do something, even if it is just stretching. Learn that it is OK to pace myself. some days that means do something, then rest. Do another thing, then rest, and so on. And I have worked hard on my attitude.
this is the hardest part. I am not some kind of Pollyanna or one of those who says dumb slogans like "attitude of gratitude", which are just annoying. but I do, every single day, look around me and feel grateful for what I do have. A home. Enough food that I will not starve. Clothes that are not tattered. Friends. A car that runs. Access to the internet. Clean water to drink. Millions of people don't have any of these things and never will.
Second, I have learned to accept what is in this moment. That doesn't mean that you become complacent, it just means you accept this as reality rather than fighting it and saying "this should not be". In the next moment, you may work to change something, but first you have to accept the facts. I have had internal dialogues with myself about the feelings of being worthless. And have come to accept that I may not be able to do everything I used to do, but that doesn't mean I am worthless. Maybe I can't build the rock walls I used to build. but I can go online and do my best to help other people. Maybe I can't be "the energizer bunny" I used to be, but I can still do my best to be someone's good friend.
And finally, I grab every single good moment I can and revel in it. If something is funny, I LAUGH! If something is cute, I take that into my heart. If the sunset is beautiful, I stand and watch it and love it.
This is what you gotta do when the things that used to bring you satisfaction are no longer possible. Remember millions upon millions of people have gone through this through fibro, or accidents that turned an active person into someone in a wheelchair, or brain injuries, or whatever. For each person it is a terrible crisis and it's the hardest thing in the world to learn to live with it. But a lot of people do learn to manage it, and you probably can too. Take heart, and be courageous to the best of your ability. Best of luck.