Major website overhauls, including 301's, are prone to crash and burn.
http://www.blackhatworld.com/blackhat-seo/black-hat-seo/355601-why-redesigning-your-site-will-you-up.html
Sorry, but at least you learned not to do that again in the future.
It may or may not recover. If you have really done proper 301's there is a chance your new site can regain the old traffic. Its a major gamble though, a good rule of thumb is don't overhaul a website that is making money unless you can afford to lose the money it makes.