If it's cold, I'll wear a balaclava, but I don't worry about getting my head wet. That seems like a losing battle. I agree with Koan about getting a short haircut, but that won't do you much good before your ride this morning. If you're unsure of your panniers or backpack, put your stuff in plastic bags before you put them in your pack. Think about packing your work clothes in a plastic bag and changing at work.
And fenders--if you don't have them, get them as soon as you can so that you'll have them for the next rainy ride.
If it's cold, PI Amfib tights keep your legs warm and dry.
Pay attention, but enjoy. Some of my
favorite rides have been in the rain.