Just wanted to let you know that, because of daycare, I have a similar problem. The first nap is short, so she wants a regular nap, not a catnap, after we get home. When she's had a particularly active day, I often have to wake her from that last nap in order to feed her. It's when I have to wake her that I get "the monster." If she wakes herself, she's fine.
We've found that there's just not much we can do to control what happens at daycare, but it really upsets me when the only time I have with her at the end of the day is "unhappy" time.