I'll keep his one short and sweet.
There will be times where pushing your limits can yield great rewards, but you cannot do this forever.
You have to take time to yourself - and make the most of it - to recharge ready to go again.
It's very easy to settle into a false sense of "rest", so ensure that you're really detaching yourself from the stresses of life to do something that you enjoy.
Don't see it as time lost in your pursuits, but time gained in the future - because you will be able to perform at a much higher level upon your return.
Taking time to yourself is also a part of the balance of life; it's normal, it's okay, and it's very much for everyone.