I have been in a similar situation and know how terribly frustrating and depressing this can be. I do have some suggestions that may prove helpful. To confirm you have RA, xrays and MRI help in diagnosis IF you have joint erosions. Your worst and longest affected joints should be xrayed first. If erosions show up MRI not needed. If no erosions seen, then an MRI of worst joint should be done.
For the muscle wasting, skeletal muscle enzymes in the blood can be checked to rule out autoimmune myositis. CK, aldolase, ALT, AST and LDH are enzymes elevated in myositis. There is then a myositis antibody panel if those enzymes are elevated. Myositis causes muscle weakness as well as atrophy. Atrophy can also occur just from immobility caused by pain and stiffness, fatigue associated with RA.
Lastly the lack of antibody response to your vaccine could indicate an immune deficiency. This is paradoxically common in autoimmune disorders that one has excess antibodies directed at your own tissues but a lack of antibodies directed At infectious agents such as bacteria, viruses fungi. This can be measured by a blood test of immunoglobulins (antibodies), IGG ,IGA, IGM. These are different categories of antibodies. If deficient one would be prone to infections and not make sufficient antibodies to vaccines. These aren’t typical blood tests done routinely. You definitely need to be under the care of a rheumatologist. Antidepressants may help you as chronic pain depletes the neurotransmitters in the brain that affect mood. If an antidepressant raises your neurotransmitter levels, then the situational problems of chronic illness may be easier to cope with. A therapist or life coach would be helpful too, as we autoimmune sufferers need someone to talk to. I wish you better luck in finding an RA treatment that works well. I’m in the same boat with lupus and RA and no response to many meds I have tried.