Giardia is no joke.
I know two people who’ve had it and they said the exact same thing, verbatim: “It won’t kill you, but you’ll wish it did”.
And they didn’t know each other.
I have a microbiologist friend who will tell you the same thing, but with (off-)colorful descriptives. Here in Iowa you have to be careful about your water, because if it isn't Giardia that gets you, there is a cornucopia of other stuff (microbes or chemicals) that will.
REminds me of the advice I heard in Hawaii for centipede stings. Get drunk for three days. It won’t help, but it might make the time go by faster.