Just logged in and haven't had time to read everything in detail. Mishap I have struggled with anxiety, depression and intrusive, horrible thoughts for decades, on and off. Until very recently I couldn't see any hope that I could ever feel any better. I had tried CBT, a year's psychotherapy, medication of different kinds, and even a dreadful 9 months' outpatient intensive Mentalisation-Based therapy at my local psychiatric hospital, which made me feel worse. I have tried Mindfulness and mindfulness meditation, which helped a little but i've 'fallen off' that particular wagon at the moment.
I know what it feels like to be in that dark hole, deeply envious of others' happiness, believing oneself to be a failure at life, walking through treacle and unable to enjoy any of the good things around me.
I see a psychiatrist regularly and he offered me a different drug for anxiety, which seemed to help even at the lowest dose. It took a couple of weeks to get used to side-effects but it was worth it not to wake up feeling anxious and sick every day. I stopped taking an antidepressant which wasn't helping but making me put on more weight, and was offered another, which is also helping - against all the odds. For the first time in years, I have some energy. I wake up feeling.....normal. I enjoy little things again. I'm not deliriously happy and still get my mood swings and have thoughts I am ashamed of having about other people. But they don't dominate as much. They don't obsess me. I don't cry all the time any more. There is plenty of room for improvement still, but I never thought I'd ever feel like this again.
So I would say to you - yes, there IS light there, Mishap, even when it looks darkest. The blue sky is still there, even if the stormclouds obscure it now. Keep going; there is always hope. You can and you will feel better than you do now.
I don't know whether you are seeing a psychiatrist but if not I would strongly recommend asking your GP for a referral on the grounds that your depression is tenacious and needs a more definite diagnosis and treatment plan. CBT might well help, but I would still insist on a referral because it will take some time and waiting is always agnonising when you are suffering like this.
I hope today is better for you, mishap