I have trouble remembering what i think about doing and when i get up to do it, i have no idea what i'm going to do. i'm 20 years old.

RU normal?: You should see your primary care doctor for a simple office test (called the "mini-mental status exam"). It's likely that you're normal. If you truly are having serious memory problems, a thorough evaluation should be done and done immediately.

Memory: There are many possibilities from physiologic to psychologic. Consult your doctor, you may need to see a neurologist or other specialist if no remediable physiologic/endocrinologic cause is elucidated.

Focus: I agree with dr.S werner and weisberger. But, you might want to see if the problem persists when you slow down and focus. Human memory is more delicate than computer memory. We must focus and avoid distraction (scattered attention) in order to remember well. If you get up to go to the kitchen but are distracted by a text message, you might forget why you got up in the first place. That's normal.