Christopher is having a hard time

I don't know what has gotten into Christopher. He's gotten very difficult the past week or so. He's been pulling a strip alsmot every day at school-granted, pulling ONE isn't HORRIBLE, but pulling one every day is just not like him. He's having trouble with homework, getting very frustrated very easily. I just don't know what to do with him. I've gotten two emails from his teacher that he's having a very hard time. Today, he's being disruptive and difficult for her. I just don't know what to do. We increased his meds just a few months ago and I really don't want to do that again this close to summer. :( He leaves every morning saying he's going to get a "Green Day" (no strips) but every day he's coming home with Yellow. I don't know what to do. He's already grounded for a week from games and computer! Ugh