Is it possible to improve memory?

I have a terrible memory. I always have but it seems to be getting worse. I can remember who I am and other important things, so don't misunderstand me. But I can't remember things relating to my day to day life like duties or chores I have to carry out, instructions given to the cl by a lecturer or by a person to me, I can barely remember and usually quickly forget. I'm slow in absorbing things now when I used to quickly absorb ideas and information. I'm only 19. What's the cause of this and how can I improve my memory?