I invested half of my saving ($25,000) into ETH when it was $725. ETH has now plunged to $459. I am very worried I will keep losing money and I fear for the worst. I want to go kill myself 
Instead of doing that, think first that it could still go up. And you made a good choice that of all the coins you have bought, it is ETH. It's the second most less risky to invest other than bitcoin and it's very possible you will recover your losses.