Hello, My 4 year old cat keeps throwing up.. she threw up 5 times in the past two hours. Nothing seems to come out, just some liquid. The last time she threw up it did contain half of a hairball treat I fed her earlier thinking it was hairballs. After she throws up she acts normally, including playing with her sibling.. Should I be concerned? She has been eating and drinking normally as far as I can tell. Should this be brought to the vet's attention?:confused: