A dream involving size usually has to do with how you feel about your position in your relationship with another person or your position in a situation.
Dreaming that you are much larger than you are in waking life can mean that you are feeling powerful, or alternatively, that you feel weak and you want more power.
You may dream that you are very large in comparison to the people and things around you when you have a need for more control over your environment.
If you dream that everything around you has become large, and you are proportionately smaller, you may feel that you are being dominated by others.
A dream that someone you know has grown very large can mean that you feel that they have too much control over a situation, or that they are too dominating.
If an object in a dream is abnormally large, think about what qualities that object may symbolize. These qualities may have become too important to you, causing you to lose some of the balance in your life.