I felt like this today. This isn't my first baby but I feel like my house is clean and organised, we have everything ready for the baby and I'm sitting at home bored (with my 2 year old). It's like I've peaked too soon.
Not sure about advice really.....how about going for a walk or swim, read some of Ina May's stuff, whatever you do don't watch "the birth channel" on TV. Or do a belly cast and then paint it, start a birth book, make some meals to be frozen (boy, I'd have to be really bored to do the last one)