The same would happen to me after eating. I finally had my Thyroid levels checked and to my and my doctor’s surprise, I was diagnosed with Hashimoto’s and Hypothyroidism. The Hypothyroidism was causing this to happen to me. I would fall asleep for about 30 minutes after eating and that never happened to me before. I am now taking 75 mcg of Synthroid to control it and it hasn’t happened again. I am over 3 years with this nightmare! No taste or smell for over 3 years and other symptoms that are subsiding, due to Covid. Due to having Hashimoto’s, which is an autoimmune disease, I have changed my diet and no longer eat gluten, dairy or soy products. It has made a huge difference in body inflammation for me and since I can’t taste or smell anyway, I might as well eliminate it and I do feel much better. I would make an appointment and have those Thyroid Labs run. Good luck!