I'm not pushing the idea of trying psychedelics (although evidence suggests they are the best treatment for many), but research into psychedelics has revealed a lot of new important insights about depression and anxiety.
It used to be that any doctor would just put a patient on Prozac or Zoloft if they seemed depressed and that was that.
Now, it's understood that about a third of people with severe depression are resistant to all known pharmaceutical treatments. The other 2/3 of people feel better to some degree when they take psych drugs. The remaining third do not improve at all.
But that doesn't mean there is no hope. It means that pharmaceutical SSRIs and MAOIs and benzos don't work on them.
Psilocybin, ketamine and ayahuasca work for many. Most people respond well to just one dose of ketamine prescribed and taken during a clinical session.
MDMA originally was used as an in-office treatment for PTSD and therapists reported that it was very effective. And then it was suddenly banned when it became popular for recreational use. Now it is recognized as being a useful PTSD therapy.
There's now also electroconvulsive therapy, eye-movement therapy and different clinical means of treating patients.
OP, if you have been taking prescription drugs and they don't work on you at all, then you are treatment resistant. That only means resistant to standard pharmaceutical drugs. Investigate other therapies.
I also just went to a book reading of a woman who wrote a memoir about living with "double depression." I had never heard of that but it is a clinical diagnosis.
Basically, it refers to people who have a chronically depressed physiology that makes the person low energy and low mood all the time, and they also cycle through periods of deep despair. It's sort of like bipolar disorder but the inverse of it. She said when she took an antidepressant, she felt a lot better, but then when she was diagnosed with double depression and given an anticonvulsant, it was like being given eyeglasses and seeing life clearly for the first time in her life.
So look beyond the obvious if you are really suffering and are resistant to treatment.