My 1 year old isn't eating so well anymore?

Ahhhhh, Teething. Can't live with it, Can't live without it! Sometimes teething can upset the baby's tummy, and it sounds like she isn't doing so well with such a sudden change at an uncomfortable time. I would give her the other bottles until the teething subsides and then decrease once again. Parenting is really just trial and error anyway. Not every child responds the same to change and just because a child is a certain age doesn't mean they are ready. My 3 yo nursed till she was almost 3, and we have been working with her to master potty training for 18 months now. Ugh. You're little one should come out of it in a week or so. Just don't let her lose weight. Good luck!