.5 is a LOT.
That will be uncomfortable for almost anyone, especially if you did it at once!
Have you ever rolled before?
Your dosing is very very off.
For someone without a tolerance, .1 to .2 will make you roll FACE. If you want to redose, take half of your initial dose about an hour later.
so say, start with .1 and then an hour later take .05.
or start with say .15 and take .075 an hour later.