Lost 11 pounds in 3 weeks unintentionally, bloated, the food i eat digests really slowly and i burp a lot, and i'm exhausted. what could this be?

Weight loss: 3 weeks of weight loss and fatigue. I would be concerned about diabetes. I think your digestive problem is secondary to metabolic acidosis. You need to be seen. It may be other things, but you need seen.

Intestinal bacteria: It has recently been discovered that weight gain or loss is associated with the presence or absence of particular bacteria in your intestines. It is possible you have a change in your intestinal "microbiome" that is related to your weight loss. Nevertheless, you should get a full medical checkup to rule out other causes of unintentional weight loss such as viral infections and tumors.