9mo switch to formula

We are 1 week shy of 9mo, so far EBF. Yesterday I had a bad day and drank wayyy to much and wasn’t able to get to my pump so went about 10 hours without breastfeeding/pumping. Somehow I wasn’t in agony. This morning LO nursed like normal, but the 2nd and 3rd feedings he just bit over and over and over again to the point where I’m bleeding and resorted to giving him a bottle from our freezer stash. Tried again tonight...got bit again but he finally settled down to nurse just one side.

I don’t know what is going on or if yesterday affected anything. Or maybe he’s just losing interest?

I guess we will try and switch to formula for the next few months because it’s not worth getting bit and fighting. My question is...I have no idea how formula works. Is it 1oz for every hour they go without a bottle? Still every 4-5 hours or so?

We eat a lot of full meals of table food and try to get variety of vitamins in his meals so I’m not really worried about the nutrients. Just about logistics. How do we make the switch? I don’t have a full freezer stash, but maybe about 100oz. So I’d like to do some mix of BM and formula for the transition. Any help is appreciated!