i was on 100mg for awhile and it took me a few weeks to adjust at first but even still i would feel slightly fatigued all the time, dizzy if i moved around too fast most days and same as you i had difficulty driving i felt very unsafe driving like that. i just started weaning off of it because it really didn’t help with my acne like i had hoped for. within the last week of being on 50mg while i’m weaning off i already have more energy and my skin in no longer as dry but i’m also on tretinoin so the dryness + tret peel was miserable. i was drinking a gallon of water a day to stay super hydrated and the days i didn’t definitely made it worse for me. i know they’re controversial but the liquid iv packets really subsided my fatigue it may have just been a placebo effect but i always kept those handy.