10m bf journey possible end? Goal 1 year

So I am extremely upset and paranoid. I have been breast-feeding my daughter for 10 months now and my goal is to get to a year. I’ve noticed a drop on my supply in the last month due to restarting my birth control and a used infection in my breast. I am worried that my daughter is not getting enough milk from my breast because when I pump at night a few hours after she goes to bed I only get like an ounce or two after pumping for 20 minutes. She is constantly coming to my breast and seems hungry. I know this could be a growth spurt but my anxiety is paranoid that I’m not giving her enough milk when she’s on my boob.

A BIG IF... If I do have to end up giving her formula for these last two months what do you guys recommend that is closest to breastmilk and an easy transition?

I am just really bummed and paranoid about this.