My cat won't stop crying!

For some reason I cannot understand much less imagine, my Siamese cat has been crying incessantly for the past few days. Ever since I changed their diet from dry kibbles to canned food, I started noticing this change in her behavior. She is not sick though. I know this because she regularly visits the veterinarian. I wonder if this has something to do with the diet change because I notice that she is hungry all the time. Has any of you ever experienced this? Even if I shush her, she just cries more. She is like a baby needing something.