What happens with me is that after a long period of having high blood sugar my body starts to see that as normal, so when my numbers first start to come down to around "normal" I get all of the symptoms of hypoglycemia (a lot of what your describing sounds like that) because my body and brain are like WTF!?! this is not the amount of glucose we are used to! I have a higher normal range that I can function at anyway. 90 is too low for me and I feel like hell, so if to be under good control for me I'm good at like 110-120. Either it will pass as your body gets used to it or maybe you need to be running a little higher than you are at the moment.