female canine crying in heat

Question
Hi, I have a bull-terrier/Australian shepherd mix. She is in her 2nd heat and I plan to have her spay next week. However, she has been acting strangely. She is constantly crying and acting aggressive towards my 8 year old son, whom is normally her buddy. Is there anything I can do to help her with her pain? Is this normal?
Thanks for any advise you may have!!

Answer
This is not normal.  Take the dog to the veterinarian ASAP.  Protect the child by not allowing interaction with the dog until this situation is resolved.  She may be entering a false pregnancy (where short term hormonal therapy will help) or suffering a heat related problem.  Have this dog SPAYED eight weeks after this cycle is resolved.  Don't DO IT NOW unless there is a physical problem.  She needs the hormonal resolution of this cycle.