And although she's feeling a bit better, she is still having trouble eating and has a much reduced appetite which has led her to seek help from a hypnotherapist.
Kate is said to be suffering from "that feeling you have when you've had food poisoning and your stomach's shrunk."
"She finds it very hard to eat a full meal and gets full very quickly," Jessica added.
"The hypnotherapy is taking away any negative thoughts connected with food from the morning sickness and replacing them with cravings for healthy, nutritious food."
And it's apparently working! Kate is now noshing down on avocados, berries, broccoli, oatmeal and smoothies. And she was also seen going for a latte and a cookie at her local Starbucks near Kensington Palace recently.
Do you think Kate was wise to seek hypnotherapy to help with her eating trouble? Weigh in below or tweet us @OKMagazine!