Relax, it's all good. She'll survive and you learned a valuable lesson. I know there are a lot of folks who still recommend deworming quarterly (4 times per year) with a set schedule of de-wormers. However, I am of the mind that you should just get fecals done a couple of times a year (spring and fall) and then administer the de-wormer you need to in order to take care of the worm load they are carrying...if they have one. There are a couple of my horses that haven't needed deworming in years because they don't have a worm count on a fecal. They are still slick and shiny and healthy. No idea if they have some weird immunity to worms or what. Then, there are others like my Taz that seem to have a pretty good load each time I have a fecal done on him
Doing it that way, only deworming when needed, helps to eliminate the resistance buildup to the dewormers. It's just like infections in humans. People get antibiotics for every little thing, and then they don't use them right, and folks wonder how we ended up with MRSA.