If you suspect CMPA, you can't introduce formula yet. Almost all have different levels of broken down dairy. The ones that are truly dairy free, taste absolutely awful (I have a CMPA baby myself), are very thin, full of additives, and often cause reflux which is a whole host of other issues. So before you introduce dairy, you need to rule out CMPA.
Be very very strict with the dairy and soy free diet. If symptoms improve, we were advised fo reintroduce dairy after 6 weeks (called it a "dairy challenge"). Have plenty of dairy, so the results are conclusive, and if symptoms come back, you need to go dairy free again.
Breastfed babies with CMPA tend to get over their allergy more quickly. And because dairy free formula is a bit problematic, the fact that you are breastfeeding already is a real gift.
I know you want a break but this is a very very short time actually. It will all seem like a blur in a years' time.
Also, it's very rare for BF babies to have CMPA. So statistically, you may do this dairy free exercise and realize she doesn't have CMPA and go on formula. Just hang in there a little bit longer.