Was My Cat Poisoned?

Question
I hope you can help me.  My cat, Oreo, was 2 years old. About 3 days ago, she started sleeping a lot, had diahrea, wasn't eating a whole lot. So yesterday when I woke up, she was breathing really fast, then she would take a deep breath and then breathe really fast again.  She was very limp, very weak....as I was going to get the phone to call the animal hospital in our area, I went in where she was laying and she had her mouth open and coughing, then she vomitted up some yellow stuff and then took a last few breaths and died.  Please help me if you can, I need to know what happened to her.  I haven't contacted the vet. Now today my other cat is acting kindof disoriented, losing her balance a little, and drinking water, but not eating.  What do you think is going on?  Please help!!!

Answer
Oh my gosh I am so sorry about Oreo, but I dont want you too risk losing your other cat so the thing I'm going to tell you to do is run to the animal hospital ASAP it may cause a good 100$ but its worth it if you want your cats alive. Also bring the dead cats body in a box to the animal hospital as well, so they can examine it and find out what is wrong. I hope I've helped, and once again I'm sorry to hear about Oreo, and I hope your other cat makes it.