I know it's hard but if you can do try and avoid pumping and bottles. Your supply will be affected and you may find you can never return to breastfeeding if he becomes used to bottles. Some people are able to exclusively pump with dedication but it is common to find your supply just dwindles away without the stimulation of the baby.
This feels bad now but it will be such a short phase. I promise. I would suggest keeping a little finger at the corner of his mouth and break him off as soon as he starts. Or even better try and anticipate. Sam used to get a 'glint' in his eye. It may not be anything to do with your supply (it sounds not). In my case Sam was just trying out a new skill!!! Perhaps in your case too.
I think with a young baby yelling 'no' is probably unhelpful though a natural 'ouch' is clearly understandable. I have heard however that some babies find it intriguing that mummy seems to make a loud noise and it might be more attractive than disuasive! I would go with a quick removal, a "gentle please" and otherwise act as normal. Another post talks about this.
https://babywhispererforums.com/index.php?topic=60914.0You could offer some muslin cloth for a bit of chewing fun. Some people talk about pulling the baby in towards the breast so they have to break off in order to breath but that sounds a bit aggressive in your case.
It will pass. Sam did it for a few days. I'm not even sure it was more than a week. He is now almost 22 months and has never bitten me since. I've never been 'bitten' with teeth. Good Luck.