He knew about the condition he was in while panicked and overdosing. It didn't have much to do with how he felt and everything to do with his state of mind and depression at that point. Ziggy is more than happy to be dragged off to his father's car and holds tight to Minoru's hand. 

"No, I can't." Ziggy is quickly catching up and may be doing as much pulling toward the door and the car beyond as Minoru is.