"Yep, perfectly fine, maybe a little tired." The Doctor replied. He was still trying to push it aside. He knew she would have noticed him cough. "Of course I'm fine." he hadn't noticed that he had already stated he was fine. He was shivering a bit. His fever was making it hard to comfortable. He knew he should probably be curled up in bed. But he really didn't want to do that. He just walked out of the TARDIS looking around him.
"Are you coming Donna?." he was looking around at the planet they were on. he was amazed by it. He grinned with excitement, even if he was ill, he was still determined to enjoy it. He grunted because of his stomach, but he wasn't stopping.

He wasn't as energetic and was finding it hard to be cheerful. His body seemed to be begging him to stop, he ended up being slower than Donna , an not really dashing ahead. He coughed again and he had dark shadows under his eyes. He looked rather terrible. He saw that there was two suns. He thought that was rather interesting, though everything in the universe was rather interesting too him.
He really did feel sick and occasionally would stop and clutch his stomach. Yeah he really couldn't seem to hide it any more. But he still didn't want to stop. He felt like he was always needed and didn't want to miss out of the fun. 

"So what do you think?" he asked her, He was trying to keep the conversation away from his health. He was sure as time wore on he wouldn't enjoy walking around because he felt ill, He breathed deeply trying to keep control of his stomach, that was threatening to betray him with each step.