Does anyone else ever get frustrated, cranky, unsatisfiable ect for no particular reason you can point out?

Today I woke up feeling funny, and no matter what I do, everything frustrates the heck out of me. Tried making some graphic art, got frustrated that it wasn't perfect, gave up. Anything I start I end up getting frustrated and bored by, like I can't seem to find anything to hold my interest in the slightest.

Its darn annoying, and frustrating in itself. I sort of feel like I have all these hours and nothing to fill them with..

I'm guessing this may be a hormonal thing - since I am pregnant. But I have a feeling I may not be the only type of person this happens to.