I've been using over a year along with a few friends

I’ve been using over a year along with a few friends. Over the summer I flew to see one of these friends and at end of destination I acquired raging head cold!! My friend dosed me up with 3 -5 drops not sure..? and in 1 hr. no cold! Now fast forward 9 mo. later I came down with crazy flu symptoms while taking a daily maintenance dosing (never miss!) and it helped but didn’t totally kill what turned into a nasty cold. It helped but not like prior…? I finally got brave and took 18 drops in six oz. of water then 1/2 later I puked. I’m wondering because I have continually dosed daily, has my tolerance to drops gone up..? So curious to know what the deal is..?