Wow, am I ever glad I started this thread! Thanks for all the replies! And yes, I AM kind of a weirdo anyway...
I think my nerves come from uncertainty of what might happen. In the country I worry about the clipless pedals and getting run over in an intersection, and in the city I worry about the crazy drivers (some of the cyclists are a bigger threat than the cars!) then there is the pre-performance adrenaline, wanting to do well, etc.
Timmhaan, I totally agree...when it feels like work, it's very difficult to stay motivated. If there's one thing I can't stand it's the indoor trainer and I will come up with any excuse to avoid it. I don't want that to ever happen with cycling!