Thanks for sharing your interesting experience. Sometimes I will have intervals where I feel normal, but cannot figure out why? If you imagine yourself pushing a cart at the grocery store, do the symptoms go away or do you have to physically push the cart? What happens if you push the shopping cart in the parking lot or somewhere else besides the grocery store? Does it need to be a shopping cart? In a grocery store? Maybe your brain is trying to process too much information in trying to maintain balance. As soon as you grab the handles of the cart, it may free up the brain for other activities. Just a thought. There certainly a lot we don't know about our brains.