Well, it could just come from napping in the day. The past few days, my WBTBs have not made me sick (though I am suffering from some serious insomnia, unrelated to lucid dreaming) but any daytime WILDs have caused that same feeling. The nausea lasts about ten to fifteen minutes max, but the sort of sick, surreal feeling, like when you stay up late with a cold, sticks around for a while after. It's extremely weird.

I guess I'll stop trying in the day, at least for a while. I'm probably also going to put my night time attempts on hold until I know I'll be able to fall back asleep.