Its just what happens when you are not used to opiates yet if you keep using them you will get used to them and it will go away.
I remember when I first started opiates I would throw up 5-10 times a day from taking too many pills and not being used to it. The way to avoid it is to lower your dose cause it means your body has taken in too many opiates and had a bad reaction or like I said over time after a week or so of taking high dose opiates consistently and puking your guts out everyday eventually your body gets used to it and stops puking. But you don't want to be addicted to opiates its no fun at all and your tolerance will only increase.