Yes, you've come up with a legitimate reason to ditch veganism. If you still have moral reasons for not wanting to eat animals or animal products, be kinder to yourself and just do what you can, instead of attacking this with too much zeal. You can be a vegetarian, even an ovo/lacto one and still be compassionate. There are many people like yourself who, for various reasons, find veganism isn't for them. You shouldn't feel guilt-tripped for giving it up, or embarrassed that you haven't stuck with it. Forget the effective gas remedy. No such thing exists.