Bike storage: It stays in my office. No one has ever complained.

Commute clothes: I have a small fan and several magnetic hooks on my office bookcase. Everything is dry by the end of the day.

Work clothes/stuff: I use a rack and panniers- gets the load off of my back. Backpacks and messenger bags are too heavy unless I'm only carrying a small change of clothes and sneakers. A computer would be way too much on my back!

Toiletries, etc.: I have a fabric bin (like you'd use in a closet) in my credenza drawer with all of my toiletries in it. I keep duplicates of my make-up, hair products, deodorant, etc. I even keep a spare pair of undies there, just in case!

Shower: I've never needed one after the ride in. It's usually cool enough, and traffic is lighter, so I can cruise. I hammer on the way home I have a small pack towel and some baby wipes at the office for any "touch-ups". Usually, the fan and the deodorant are enough. I have super-short hair, so I can't help you there...

Fear: I was definitely scared the first few times. It got easier each time, and now I look forward to the days that I can commute by bike. Slap a bunch of lights and reflective tape on your bike, ride defensively (signal, stop for red lights/stop signs, control your lane), and act like you belong there. You'll do great!