Your body is fragile. Give it lots of rest. Exercise should be moderate, and your schedule shouldn’t be hectic. Manage your health in a sensible way. Pay attention to how your body feels. Listen to it.
There’s a belief in the fitness world that the body is lazy and it’s the person in the machine controlling the gears that needs to force the body into action. I don’t buy it. The body knows better than we do. You can push it further than it wants to go, but you’ll pay the price if you do.
There’s a time to push yourself, but not for aesthetic reasons or arbitrary physical feats. Incidentally, the desire to accomplish physical feats is often an overcompensation for insecurity. The fear of not being good enough. The fear of not mattering. Not feeling loved. Ambition, in general, comes from such insecurity.