The Hills alum Kristin Cavallari, who shares kids Camden, Jaxon and Saylor with ex-husband Jay Cutler, shared a funny TikTok video Jan. 6 where she contemplated if she wanted another child. Kristin Cavallari may have a case of baby fever. The Hills alum—who shares kids Camden, 12, Jaxon, 10, and Saylor, 9, with ex-husband Jay…