If you dream that you are drowning, you could be feeling that you are in a situation over which you have no control. You could feel that you have been placed, or that you have placed yourself, in a situation that you cannot handle by yourself.
Water often symbolizes the emotions in dreams, so drowning in a dream can symbolize being overwhelmed with emotions. You may be under a great deal of stress and are bottling up your emotions so much that you are afraid that you will not be able to contain them and that they will overpower you.
Drowning in a dream can also symbolize a loss of identity, or a loss of ego. This can have negative connotations, meaning that you feel lost and unsure of who you are, or it can have positive connotations, meaning that you feel at peace and in harmony with the world around you.