Quiet mysterious attitude. Don't act angry. Lost in your own thoughts. Busy with OTHER activities. Offer nothing emotionally or doing any work for him...
If he asks you what is up with you..
"Oh nothing, just got a lot on my mind..."
"Oh nothing, just doing some thinking."
If he asks you about the clothes and making his dinner..
"I decided that I am not going to do that anymore for you. You are a big boy and I think you should do those things for yourself. I have too much else to do>" (said matter of factly and without anger.)
Then get back to whatever it is you were doing. If he pressures you for more information...
"I just don't feel like talking right now about much of anything. I just have a lot on my mind."
If he asks you if you are mad at him
"No, I'm not mad at anyone. I just have a lot on my mind and a lot going on."
Calm cool resolve. Quiet mystery. Hold BACK on any discussion and stick to the plan of telling him "I have a lot on my mind"or "I don't know what is wrong with me, I just don't feel like talking right now."
You don't act sad. You don't act angry. It is a quiet lost in your thoughts attitude. You can NOT have a relationship talk YET. (that will be coming but you have to "set the table" here for it to have maximum effect. He probably isn't going to be too concerned initially because of your pattern of interacting. (which MUST change for good for now)