Thanks for responding everyone! c:
All my cats are officially sick. Last night, Sassy threw up and they all refused to eat, no matter what we tempted them with. So they all got fluids, medication for nausea, and appetite stimulants (all this was give to us by my aunt, who's a vet.)
They seem a bit better this morning, and the strain going through my cats seems to be less serious than the one that went through my aunt's cats. They're all eating a little food (except for Sassy, who still doesn't seem like she wants to eat at all) and Bramble even seems to be getting his appetite back, and none of them have a fever. There has been no more throwing up, and hopefully they'll be better soon, though we're continuing to give them medication (thankfully, Jigsaw, Bramble, and Amarni are good for their meds. Sassy and Butterscotch, however, are not xD //after only medicating them for one night I already have scratches across one arm. Although, luckily, after growing up in a vet clinic, I have been scratched by many a cat so it doesn't bother me x3)
Cats do get flu-shots, but I don't think this is an ordinary strain of cat flu, as, like you said, woospuss, they do not have runny eyes/noses. They're not going to be checked by a vet unless they get really sick, as my mom was my aunt's vet assistant and I can help her check and medicate the cats. We and my aunt are also quite certain it is the same bug that went through my aunt's cats ^^
Anyway, does anyone let their cats outside for an hour or two in warm weather? Before they got sick, my cats were going crazy not being able to go outside. They had kitty cabin fever xD