Lipitor and hot weather

After stopping Lipitor AND Fosamax, Ihave regained the ability to walk down the stairs without holding on to the hand rail.I have also regained the flexibility in my knee joint which had been very painful when I squatted down.I was previously unable to get up from the squat position without holding on to some support.
I have noticed people remarking on legs turning and feet tripping over things if feet are not picked up sufficiently. I too have these symptoms but was not noticing them as separate side effects.
My general mental fog has been remarked on by people with whom I play Mahjong and Bridge . I seem unable to remember things for very long.I have also had one episode of the room spinning round while I was seated. Is this another side effect or just the result of hot weather and dehydration????
PG
Australia