That does worry me a little. I've had office jobs for years. It's been a while since I've done manual labor. But I am just going to do what I can to stick with my plan. Who knows, I may be able to last longer than a few weeks.
I wanted to quit every single day my first three weeks. Now there isn't a job in the building that intimidates me. No matter how bad it seems at first, you get used to it, and it does get better.