Every time I get stressed, I want to meltdown/die...

It's all about vibration, though you can read any book you like or is recommended. If you can't change your situation, change your vibration. Focus on different things, or try to see the good in bad experiences (what have you learned from this moment, and then taking this lesson to move on with your life). Also best things to do, better than reading any book, is going for walks into nature, and spending some time with your pet. And quit drinking sodas and coffee, switch to drinking water and tea instead. Drinking a glass of water while you're stressed can also reduce stress. And the best tip of all: sport, excercise! Swimming, running, fitness, basketball, tennis, whatever sport you may like, it really helps. But if I was to recommend a book, to answer your question, I'd recomment "Live in the now" by Eckhart Tolle.