Dear T.,
I'm sorry to hear your little one has been sick and I hope he'll be feeling better soon.
My mom always said that when a kid starts biting, it's time to stop nursing. Believe me, the first time my son clamped down on me, I was ready to be done. However, I pressed on. But, every time he bit, I told him "NO BITING", took the breast away, and gave him a teething ring or something else to bite on. I did it EVERY time.
He truly did get it figured out that mommy's boobs were not for chomping and I happily nursed him until he was 15 months old. If he hadn't quit biting, I would have stopped nursing sooner, but he got the hang of it.
Your little one may be biting because he either isn't really hungry or he just doesn't feel good. Try giving him a bottle with water in it or offering a teething ring so if he wants to bite, he can, but he just can't bite you.
Since he's already getting breast milk in a bottle and nursing at night, I wouldn't worry too much about it for now. Just keep doing what you're doing and hopefully, when he feels better, he'll go back to nursing without biting more often.
Best wishes!