[Mistressfreeze]

So Xena is a picky eater. She only eats when she's hungry and every now and then I have days where she picks at her food or doesn't eat her breakfast because too much is going on. This week she has been exceptionally picky at first I did not think too much about it but the last few days its been a struggle getting her to eat. She's turned her nose away from treats, if I do get her to eat something like sliced apples its one or two little pieces and she done. I've had to put bits of hot dog or cheese in her food just to get her to eat and that has only really worked for supper now. Aside from her lack of appetite Ive noticed that she's tired. She lays around on the couch all day, usually she has her spurts of energy where she runs around or barks at me to get a toy but she hasn't had that the last two days at least. She still gets up and follows me around or to see if someone's here. However, this morning she threw up and its possible she was running a fever yesterday (its hard to tell because my sister had her dogs over so she could have been worked up barking at one of them).

I have switched out her water bowl to a smaller one so I can measure how much she's drinking. I read online giving her aspirin is a bad idea. Is there anything I can do or give her to help her feel better?
Also my sister's two dogs previously had a cold. Is it possible this is just a cold that will take its course or should I be concerned its more serious?