It is probably whatever bacterial infection she has that is probably making her do this, not the Melafix. Melafix is the gentlest meds there is. There's just no way--unless you overdosed it--that it could be killing her.
If you added it right on top of her, though, it may be her freaking out from the osmosis of a concentration of the meds. It's better to water it down a little first before adding it.
