Not experienced as i am new also, but your experiencing similar to me, mild to moderate headaches and feeling wishy washy, i have also had shaking, slower than a shiver, have posted on here and shouldn't be too much to worry about, but if you are worried speak to a medical person, like you Doc or nurse, i keep a diary of all my bg tests, what and when i eat, and also any side effects.
You will probably find its either any medication and/or your body getting used to the lack of sugar.
Some with more experience than me will give you a better answer i am sure.