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 
I do not see why you should be so desperate in that situation, since you made the right decision not to invest all your capital, so even if ethereum were to be worth zero, you would still keep half of your capital, enough to do still many interesting things.
But for your fortune, ethereum has strengthened enough recently to allow you a gradual recovery in your investment, but I also believe that this is just the beginning and I am convinced that by the end of the year you may be able to multiply your investment x2.