Need dosing help

I can't find a solid answer on this but I want help before I go poking, prodding and overall giving my girls any type of chemicals.

I dewormed my girls with liquid safeguard for 3 days when I first got them (a month ago). The vet said they appeared healthy and they did mention their gums/eyelids being pale but I told her I just started giving safeguard so she said ok let's go from there than. Well my girls have been eating fine and are plenty active so I didn't think anything of it, they are kinda shinny though. However last week I noticed their gums are white!

I read this could be either worms or lice that are causing them the anemia. I did a fecal at home and really didn't find anything, I was talking to their vet who said try Adams flea/tick spray if I see lice, which I don't but I got some and treated them anyways with it. I have injectable iron and vitamin b complex on hand that I can give them, but they just took an iron capsule on Tuesday so don't want to overdose.

I ordered generic ivomectin injectable which should be here next week but I was told if they are white not to give orally but inject it. Is the injection amount the same as the oral amount? And can I give the iron and vitamin b at the same time?

You can give the iron and vitamin at the same time, but I can't really advise on the dose of injectable ivermectin as I have never done it.