I haven't, but I also started out slow. Try lowering your dosage until you tolerate it better, or wait for a little altogether (listen to your body!)

Are you making sure to have organic acv? Apples are literally the most pesticide ridden of all the fruits and vegetables; if its not organic you could be reacting to the pesticides inside it.

Acv is most beneficial with the mother, as it is probiotic.

Also cold mean you have high stomach acid, in which case you might look for ways to lower it naturally.

It might be die off, but it also might not be. See if taking vitamin c helps :)

ACV can act as an antimicrobial so it is likely acting as that. It is also a probiotic which helps populate good bacteria. Perhaps your problem is not parasitic but rather bacterial or yeast since ACV is not known to kill larger parasites.

I would continue the ACV and consider increasing sIgA by taking colostrum with Vitamins A & D if the ACV stops working.