Fret not. I majored in finance, joined the industry a year plus ago. During my first 4 months, i lost my voice constantly, due to stress (according to 4 different doctors). Sleep early, do not think about work when you get home. Do whatever you enjoy doing during non-work hours. You'll pull through. You do not have to speak to anyone, just yourself. You will get use to it, your body will get use to it, your mind will too.