There are several different possibilities here, but I would definitely recommend getting in to see your primary care doctor
to get a complete checkup.
In college (and high school), many people experience disturbances in their daily and nightly routine due to homework, studying habits, and social life. As a result, many people stay up quite late at night and may get less than optimal sleep, which could lead to excessive daytime sleepiness
. I would start by taking a look at your sleep schedule to see if this might be going on.
Insomnia is another (sometimes closely related) problem, and this could be related to stress or to use of stimulants such as caffeine. Alcohol can also impair the sleep cycle and disturb nighttime sleep schedules.
There are also some medical conditions that can be associated with daytime sleepiness. These include obstructive sleep apnea
, especially if you are overweight or have a tendency to snore at night. Narcolepsy is a rare condition characterized by sudden and unpredictable fits of sleepiness during the day.
As you can see, there are a number of possibilities. Therefore, the best thing would be to talk about your symptoms to your doctor and see if further workup or treatment is needed.