As it turned out, I did re-write the whole line and said "I'm happy today" ... totally avoiding the (could be confronting) use of 'gay'.
Quite sadly, it's a fabulous word that has now almost entirely lost it's delightful original meaning.
I was asked in an office if I was gay, once. (impertinent, I know).
My answer? "Well I'm moderately cheerful, not sure about gay ..."