Screaming 6 year old

[NjMK]

My son just turned 6. One or two day's out of the week he is well behaved and the rest he is screaming, yelling,winning, & mean! I don't know what to do. In school he listens and does what he is told but lately he has not been following direction from the teacher. I have recieved several notes home from the teacher. She says he is a pleasent little boy who for the most part listens & does what he is told. But then on some days He is like Jekyl & Hyde.
  We are normally a household of 4. My husband, my 6 year old, my 2 year old and myself.  Since July my sister and brother-in-law and their 11 year old and 14 yeard old have been staying with us due to my brother-in-law's job loss.  My sons behavior has changed over the past 7 months. I've also been ill and going to a lot of doctors and when I am not feeling well I am on the couch. That is when I see my son very kind and caring. I know he is dealing with alot. Having extra people in the house, having a sick mother and school.  
  He wakes up most mornings mean. He wakes up in the middle of the night and comes to sleep in my bed and says he's wants to cuddle and he misses me. That is when he is sweet. Some days he listens and he is soft spoken. Most days he seems agitated and upset. Yells out his questions, screams his answers and just doesn't listen. Yesterday he ran out of my mothers house, my mom was calling him to stop, I came to the door and told him to stop running toward the street. He turned, looked at us and continued to attempt to go into the street as if he was testing us or as if he deliberatly was not listening to us. I ran out and grabbed him by the arm and brought him into the house. I then explaned to him how dangerous it was for him not to listen to us with the cars an all. At first he acted as if he didn't care, then he apologized and said he wouldn't do it again. This morning was another argument for him to get ready for school (kindergarten) along with the screaming and yelling.  I really do not know what else to do. Time-out doesn't work anymore, scolding, taking items away that he likes doesn't work either...Help!

[margypops]

Could there be any connection between the older children coming to stay and his behavior have you noticed how they all get on, are the older children kind to him any teasing,bullying,  check out if there could be. It may be a good idea to set the alarm clock earlier a lot of children fiond it hard to get ready in the mornings, and if he has more time it will work better, are the other children well behaved , has your son his own room or does he have to share? The dynamics may need some checking on, it may not be all his fault. Is it possible in the near future you will get your house back to your self, you may find that will solve the problem, meantime dont place all the blame on him, focus on his positive side and praise him when you see him doing something right. Good Luck