How can I cope with fatigue after thyroid cancer surgery and treatment?

Hello! July 14 I had my 2nd surgery to remove my thyroid and 3 parathyroid glands. Diagnosed with Minimally Invasive Oncocytic Thyroid Cancer, a rare and aggressive form also known as Hurtle Cell. Taking 150 mcg which will soon be increased to 175 mcg Levothyroxine to suppress my TSH and trying to fight the overwhelming and total fatigue which makes it hard to do anything and the accompanying brain fog. I’ve had good news re no pathology in the second 1/2 of the thyroid removed in July (first was in May to remove 4.3 cm tumor from left lobe and the cancer was found) and that all lymph nodes are clear. The cancer very slightly had escaped beyond the capsule of the tumor, but as there were no blood vessels present in the tumor my surgeon is confident that the cancer did not invade my vascular system. Being 75 elevates my risk of metastasis either locally or distantly. My Dr. presented my case to the tumor board (excellent hospital connected with Dartmouth Medical School, Mary Hitchcock Hospital) who all recommended Radioactive Iodine Treatment to kill and remaining cancer cells and light up any metastases which might be present elsewhere. My concern is the multiple risks of RAI considering this type of thyroid cancer isn’t receptive to RAI, even after a Low Iodine Diet and discontinuation of all Levothyroxine and injections of Thyrogen to raise my numbers of TSH (?) for optimal reception of the Radioactive Iodine, as success rates are generally only 20% or so. I have a number of autoimmune diseases most significantly Mixed Connective Disease which in my case presents as Rheumatoid Arthritis and Systemic Lupus Erethmatosis (so..,I usually just think of this as SLE). Also have osteoporosis and osteopenia (different areas). In addition to pain issues I just deal with more troublesome is esophageal dysphagia which periodically makes swallowing a difficult, painful and embarrassing Olympic event which I never know when it will occur. There is also a motility issue (lack of) at the other end of digestive tract resulting in chronic constipation managed by Linzess and dietary changes. Having no thyroid now makes this worse. Even at 75 I have 2 fulfilling and challenging jobs I love and keep me active, Professor of Music at a college teaching courses, piano and voice and directing the college chorale, and Director of Music (choir director and pianist) for a historic church. Thankfully at the time of diagnosis (discovered in imaging for a different issue related to migraines) my college was on break for the summer, but resumes in 2 weeks. It’s been very difficult just to maintain my work at the church and needed a total of 3 Sundays off for recovery from both surgeries and adjustment to the incredible exhaustion with the Levothyroxine. Thankfully this semester I will only be directing the college chorale, but this requires a tremendous of energy both mental and physical. Gratefully both the members of my choir and leadership at the church where I’m employed as well as my fabulous students in the college chorale are incredibly supportive. So, this is my situation and introduction to my particular cancer as well as current concerns and challenges. Are there others here with Oncocytic Thyroid Cancer, and have had Radioactive Iodine Treatment? I look forward to “meeting “ you and learning how you are doing. 🥰