Please watch What The Health and Cowspiracy. Veganism is the ultimate rational decision. Aside from eating meat and dairy being awful for your health and costing health services millions, animal agriculture is the leading cause of climate change - bigger than all the cars, planes and trains put together. I know this isn't what you want to hear - believe me. When I first found it about this stuff and the person I'd watched Cowspiracy with said 'we have to go vegan, don't we?' I was like '...do we though?' But to be honest, the answer was yes. It might not be easy at first but it's the only rational (and moral) choice. You live on the planet, you should help look after it.