I have terrible memory, is there anything I can do to improve it?

I probably had pretty average, normal memory..But uh, I can't remember when my memory got lost..It's steadily getting worse, though...I can't remember a dream if I don't write it down asap. I often forget what day it is even during school weeks. I do badly on tests unless I cram every night. Sometimes my memory is so bad I even forget what I ate for breakfast the morning of that day.