I have two stories I am writing right now and there is a third one in the background "on pause". Sometimes, I need a break from one of the worlds I create and it isn't hard for me to move between them. However, when I go back and reread to edit, I find some similarities. For instance, I must like the name Alex because I have three different characters in three different stories named Alex (all male). There is one Alexa as well in a fourth story. I also find lasagna is a popular dish for my characters to make or for their parent to make. I have no idea why! Maybe because I like it? Or, it can feed people over a few days?
Are you able to have multiple projects going at once? Do you have a common theme or find similarities, like above, in your works?