I know EXACTLY how you feel! I have only been vaccinated, no booster (my side effects from the vaccine were horrible, didn’t want to go through that ever again). My symptoms are all over the place, horrid sinus, head and ear pressure, heart palpitations/arrhythmia issues, gastrointestinal problems, all over body pain and aches. Episodes of lightheadedness, balance is off (which I believe is from the ear pressure), internal tremors, was recently diagnosed with a some level of Dysautonomia, said part of my nervous system is malfunctioning. Other than my Cardiologist saying that from numerous heart monitors they see some disruptions but nothing life threatening.
But I’m with you tried of sooo many doctor appointments and tests for them to say they really can’t really do anything to help my symptoms or see anything “life threatening” but when those symptoms are at an all time high I feel like my life is in danger. So I have given up and trying to accept that this is my life now and grieving a life I once had. Almost three years for me, so sad and frustrated.
I wish you better health and happier days ahead.