The OP states the virus mutates which is true, but the vaccine still provides antibodies to fight off influenza if infected. This vaccine is mandatory in US hospitals because influenza is devastating to sick and immunocompramized patients. The OP may have had and may continue to have issues from the flue shot, or more likely is experiencing an autoimmune/anaphylactoid reaction from an unknown illness or disease. Let's don't forget vaccines 100% save lives and prevent overall mortality.
RE: Flu vaccine and a real life adverse reaction