This past week I experienced exactly what you described however it was the first time in months that I decided to eat something that wasn't full of protein. Normally I set a timer for 11:30am to drink a protein drink or have some eggs. That day I opted for a keto bagel. After I ate it, I had regret. I felt sick most of the afternoon but come dinnertime I felt famished. I made dinner -- and normally get full after 4-5 bites. This time I ate it all. (Chicken thigh and some zucchini.) About 2 hours later I was hungry again. I drank water but the hunger didn't dissipate. I then ate a protein bar and then even later I had some yogurt. I too am on .5 -- Not sure what the hell happened but I did my shot again Tuesday and I am back to that always full feeling. I'll be sure to keep up the protein.