Marijuana can increase a person's hearth rate almost 100%.
It could be due to stress. Everyone deals with stress differently. Usually they are mad at themselves, like they have failed at supporting and that can lead to depression also.
You would definitely underweight. The villi in your small intestines increase intestinal absorptive surface area approximately 30-fold and 600-fold respectively. This provides exceptionally efficient absorption of nutrients in the lumen. This increases the surface area for food to be absorbed. So if there were to be less villi you would underweight.