PLEASE HELP ME!! MY CAT!!!?

OMG! I am so so so so scared! i Only had Lizzy (cat) for 2 months. She is 10 years old! and she was laying down on my bed, and all of a sudden her head came up and she started breathing hard and it was really weird. Her stomach was going in and out while the weird breathing was going on! I AM SOO SCARED!!! I cant explain the sound she was making. but its like when a human has a cold with mucus in its throat and trying to cough it up. That is the best way i can describe how she was breathing, and her stomach was going in and out ! I am sooo scared. This is my first pet. She is 10 years old and i got her from her previous owner and she has been with me for the past 2 months. PLEASE HELP!