Leeches in your dream bear a double significance: as energy and positive emotions' drainers - and here we have a negative significance - or, when used for medicinal purposes, as tools to help us improve our life and condition.
If in your dream you see leeches glued against your skin who suck out your blood and make you weaker, they stand for things, situations or people in your waking life that drain you out of your energy and resources and do not let you 'function' properly. The leeches may also stand for negative emotions and overall pessimism which dominates you and keeps you from evolving. You should try to eliminate these 'leeches' from your life if you want to achieve happiness and attain all your goals more quickly.
If you see your body covered all up in leeches which hurt you this means that the little sticky and disgusting animals represent your remorses or the 'stains' on your soul, your feelings of guilt, regret etc. Or that you are simply not at all satisfied with your body.
Leeches which bite you in your dream may also forewarn you of hidden danger which lurks just around the corner and is anxiously waiting to attack you. This may refer to false friends who plan treachery on you or to unhappy events to come up soon in your life. One way or the other, if not extremely careful, you will meet sorrow, grief and disappointment soon.
On the other hand, we should not forget that leeches have been used since centuries ago to drain infection from a sick body and make an individual healthy again. Therefore, the leeches may be the tools to 'suck out' the negative emotions and pessimism out of you and let you in a positive state of mind which is going to further allow you to accomplish and fulfill all your dreams and ideals.
But leeches against your body in order to cure you may also announce poor health and sickness. If they are glued against your body, this means that you are going to suffer soon from health disorders and if the leeches are stuck against the body of your friends, then they will experience ill health and complications.