We have - yet again - the US-UK linguistic divide rearing its fascinating head again.

Pyjama is the usual spelling for us Brits; and "having the hump" is a very old-fashioned way of saying that you are in a foul mood.
('Tis an expression that my Mama used as well, Bingley! She used to recite a comic poem about "... you'll get the hump, the camelious hump, the hump that is black and blue." For the life of me, I can't remember the rest of it - any offers?)