I coded for about 5 hours this afternoon, a POC for a bigger product idea I have been doing research and planning for for about the last week. It's a tiny Ruby CLI, and I'm not sure it proves any concepts yet. (But it runs and does a thing!)
It felt great to be in flow for that long, but now I'm exhausted and can barely focus on the screen. Solo dev'ing is all energy out, no energy in.