I have hashimoto's and hypothyroidism, my anti-TPO is 822, TSH is 0.8 on 150mcg of synthroid (thyroxine). Why do I still suffer from night sweats and leg edema?

Probably not thyroid. Looks like your hypothyroidism is being properly treated. The anti-tpo antibodies will stay high for a long time. I don't see how your symptoms are related to the thyroid. Suggest discussing this with your doctor.