I'm not sure what you're wearing at the moment, but I find that lycra stuff tends to dry out really quickly just hung up on a coat rack in the office. My rainy day kit is lycra shorts, base layer, waterproof cycling jacket (dries really quickly), gloves and waterproof overshoes. The gloves are still wet by the end of the day but it's not usually the worst thing in the world. Keep a towel at work to dry your legs off.
Once you have all the kit you need, cycling in the rain isn't bad at all. Certainly better than being sat in traffic that's slowed to 5 mph just because the roads are a bit wet or slumming it on the bus where everyone seems to smell like a wet dog.