Can't seem to stay awake for more than 12 hours for some reason. sometimes sleepy after 5-6. sleeping 8 hours while not doing much but sleepy all day.

Sleepier & sleepier: Many causes: nonrestoratve sleep, medications, ongoing medical illness (es), emotional illness esp depression, and exposure to environmental "toxins." The chronology of its onset coincident with other "events" may further define tcause. Introduction of medications about that time, onset of snoring, purchase of new pet, sullen more hopeless mood, other physical or emotional symptoms? See MD

Investigate.: There are myriad reasons to feel sleepy during the day despite adequate sleep duration. Sleep apnea, slow thyroid, vitamin deficiency, anemia. You need some investigations via your PMD. Remember that sleep is not only about quantity but also about quality. Eight hours of poor quality sleep will still render you quite tired during the day.