This makes me suspect that my cat Patches did indeed have the flu after all back in September. Coincidentally, my daughter came down with the flu shortly after we noticed the cat was ill, then I came down with it.
Fortunately, Patches made a full recovery too. She lost about 1/2 pound during her illness and had the shivers for about 2 weeks total. I ended up giving her some kitten formula for about 10 days in-between meals to stop the weight loss. I was afraid she was heading towards hepatic lipadosis. The kitten formula worked like a charm. She happily lapped up a few ounces at least 3 times a day. She's regained the weight she lost and we're working on weight loss now. She currently weighs 11 lbs and should only way 8 lbs max (she's a little thing).