To fix the Vitamin D and Vitamin B12, go to a local health food store and find supplements of these. The best form of Vitamin D to get is Cholecalciferol, or Vitamin D3. And if I were you, I'd try to take at least 1000IU/day, and you may need more initially (the Endocrinologist told us that the body uses between 2-4000IU/day, and sometimes more).
Vitamin B12 can be taken sublingually. It is inexpensive and safe to take in large doses (your body won't absorb what it doesn't need). I personally prefer the methyl-B12, but cyano-B12 (cyanocobolamin) is fine for most people. Look for a supplement that has at least 1000mcg. per sublingual tablet.
Foods high in Vitamin D include oily fish (salmon, tuna, etc.) and sea vegetation (such as the dark stuff that sushi is wrapped in sometimes). Foods high in Vitamin B12 include meats and liver, but food-sourced Vitamin B12 requires adequate stomach acid levels, a healthy stomach lining, and a healthy terminal ileum (the last part of the small intestine) in order for it to be absorbed.
I'm surprised your doctor didn't offer you prescription versions of these nutrients, because being low in both can cause low energy, and low B12 can lead to permanent nerve damage if left untreated.
And for the thyroid, a simple iodine supplement may be helpful, but you might want to consider prescription thyroid support in addition...it might be good to talk with an Endocrinologist about your thyroid test results.
I hope this helps - take care,
Chronic Lyme Disease, Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication/Chemical Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD ("Secondary Lupus-Like Syndrome"), Osteoporosis, Pancytopenia, chronic malabsorption/malnutrition, etc.; G-Tube; Currently TPN-dependent.
Meds: Zofran, Pulmicort, Heparin (to flush PICC line), Claritin, Colloidal Silver (used topically), IV Milk Thistle, probiotics.