Where do I begin?

I have NO idea where I begin today. I feel myself slowly drowning in work and questions that I cannot answer. I have never felt more incompetent in my life yet, I feel like I am over worrying, over concerning, and just plain over the top on everything! Its one of those days where I sit staring at the screen wondering what the hell do I do today? I have a TON of things to do yet I am stumped with questions rolling around in my head. Is this an age thing going on or am I just becoming 'stupid'??