I'm having the same bugs. I do use CC and Mods, but observed a few things:
-The hunger has always been an issue since I made the sims it seems, or at least very soon after (both my Vampire Sims were made in CAS)
-The tired/exhausted moodlet only recently started showing up, for all of the vampire sims in my current household (the only household I have really played so far, to be fair).
-Sleeping/eating/make happy cheat do NOT cure the bug. I have tried this, multiple times, various strategies - sleep in bed for ages, make happy, etc. However, it keeps coming back.
-I have removed my mods - but not all my CC at the moment, I may attempt it, but from the sounds of it, it's a game bug
-My sims have always autonomously cooked (very annoying with the withered stomach weakness)
-My sims have only recently started autonomously sleeping, since the exhausted moodlets have showed up
-I have made some previous saves and I will check if the bug exists in those saves, if not, if I can figure out what has caused it
It is very annoying, especially since it somewhat breaks my story and my sims get tired very very quickly. So I hope it gets fixed!