Wiktionary
a. In a state of nervousness or anxiety.
Usage examples of "in a lather".
Ser Wendel Manderly was all in a lather to know what was happening.
I stood for a moment in a lather of indecision (the name I would like, incidentally, if I am ever ennobled: Lord Lather of Indecision) and decided to venture up the drive a little way - just enough to at least glimpse the house which I had come so far to see.
I was in a lather of perspiration by that time: the lady down the car was still dangling and talking about it: still nearer a feminine voice was giving quick orders in French, presumably to a maid.
Having gotten everyone in a lather by interfering with nature for years, it has decided now not to interfere with nature at all, even when that interference would be demonstrably beneficial.