Refer to my tutorial section on the Digestive and Elimination System . The rat in the dream is the threat but the fact that it is dead indicates the threat is being taken care of by your immune system. Although you are not aware of how it got killed in the dream you can be thankful that your immune system is working well for you and looking after your body. In reality the rat represents cancer. This may seem shocking at first but remember that dreams exaggerate and that the cancer was shown as dead in the dream.
Dreams can even warn about such conditions many many years in advance of the disease.
This gives the dreamer plenty of time to take remedial action to prevent the condition from ever manifesting. The dream shows your husband helping you with the problem. This usually indicates that you feel you are not getting enough support from him. Talk to him about your concerns and any stress you may be feeling as this is contributing to your condition. So my message to you is to go for a check-up to be safe.