What Causes Dizziness, Headaches And Clogged Sinuses?

have had a myriad of symptoms over the past three weeks. It started with heart palpiations, dizziness, jaw pain, headaches. the jaw pain subsided 75%. Then it went to diarrhea, muscle aches, sinuses clogged, yellow snot, shortness of breath, muscles twitching, dry eyes, eyes twitching, joints popping constantly, woozy disoriented feeling that I cant quite describe almost all the time. My life has been put on hold and I feel like I would be better off dead at this point. I am scheduled for an mri, ANA test, lymes test, ct of stomach. etc. my questions are; firstly, do these symptoms ring a bell as to what could be my issue? Also, is it possible that a virus such as the flu could last this long? thirdly, my PA prescribed me prednisone 50 mg for 5 days for the inflammation of sinuses/digestive tract. I am scared to take it in fear that it may add to my symptoms, and that I can not bear. would prednisone be something you would prescribe for these symptoms/