From what I read you will not be burning ketones (which you want to do) if you carb up every so often. It will set you back.
When you get though your first 2 weeks, your strength and energy will come back.
I take magnesium and never have a problem with constipation.
I was a real sweet tooth type also but now 1 square of Lindt 85% chocolate is my fav dessert and is very low carb.