Learning is a painful process. It is natural to feel stupid when learning so it's important to prevent your ego from trying to "protect" you from the early follies of learning. In time, this process will humble you and make you a better person. You may even come to like it.
Follow your passions. More often than not, you'll learn and "stay ahead of the curve" just by learning adjacent subjects to what you care about. Don't learn anything you are not passionate about (within reason).
Look after your health, nothing else matters more, that includes mental health as well.