I'm sorry you're struggling so much. My birthday is coming up as well and I'm completely dreading it. I related to a lot of what you said. I also struggle a lot with just making it day by day. I used to be and still am somewhat a very goal directed person, so I struggle with not working on accomplishing everything I "should" everyday. It's definitely a day to day thing.
What have you tried med wise? Have you tried augmentation with some of the lesser used, but sometimes effective meds - thyroid meds, stimulants, lithium, atypical antipsychotics?. Sometimes you need to hunt around with a doc until you find one who's willing to be creative. There is also ECT, transcranial magnetic stimulation, light therapy, exercise, talk therapy and ketamine. Ketamine is much newer and probably hard to find, but there are studies out there being done.
Have you had a medical eval to rule out medical causes like hypothyroidism or anemia? Those can be pretty easily checked for.
Sometimes a second opinion at a decent sized teaching hospital is helpful. They tend to be up to date on the latest and greatest.
Hope you feel better soon.