I've had really bad dihhrea and upset stomach for the past 2 days and on the 2nd night i pooped in my bed when i was sleeping. what could this be?

Viral/food: This could be a viral infection or perhaps you ate some bad food. Both of these should clear up in 2-3 days. If it does not you need to see your doctor.

Diarrhea: Likely gastroenteritis, Did it start after eating somewhere? Are others around you ill as well? How often? muddy or watery or bloody? Consider , bananas,white rice, toast applesauce. Consider probiotic to replenish gut w/ sachacromyces boulardii, lactobacillus rhamnosus, B longum, B bifidum . Hydrate w/ 3-4 liters/d water/ gatorade. May need stool culture/ antibiotic. F/U w /MD /urgent care