At 21 years of age it is unlikely that you are going through a growth spurt. Therefore, I think it is worthwhile for you to go see your primary care doctor
for a checkup on these symptoms. If you have not had an annual physical
in a while, this would be a great opportunity to schedule one.
Your doctor will be able to look at your weight to determine whether it is going up or not. If it is going up, this makes behavioral causes of your increased appetite more likely - such as stress or boredom.
On the other hand, if your weight is not going up despite eating more, then there are several additional possibilities. In the absence of additional symptoms, an increase in exercise will spur an increase in appetite. If you have not been exercising more recently, there are a few medications that can cause increase in appetite, so you should review any recent medication changes with your doctor. Also, there are several medical conditions which can cause increased appetite, including diabetes and problems with the thyroid gland. Your doctor will probably want to perform some basic blood tests, in addition to a physical exam, to investigate these possibilities.