My Cat sounds like she has something in her throat?

This morning I was horrified to see my cat keeled over and wheezing/coughing. It sounded like she was trying to get something out of her throat. I picked her up and patted her back and she purred but it sounded like when you cough up phlegm. What wrong, she's only 1 and otherwise perfectly active as usual. Is it time for the vet?