I love my wife dearly and really want to save our marriage but don't know what to do when she is so adamant and nasty. She refuses everything at the moment.
The key sentence is that she refused everything at the moment. So you've been suggesting do this or that (marriage counseling, going out, etc)? If so, stop. She won't do anything for this marriage until she's ready.
Your first step is to diffuse this anger of hers. She won't see past it. How to do that? Give her space and remove any pressure. Don't be obviously hung up on her and don't go overboard trying to initiate conversations, etc.
While you are giving her space, give yourself permission to focus on yourself. Find activities that you enjoy. Work on the issues that troubled your marriage. If you are depressed, go to the doctor and get some anti-depressants to help lift your mood. Don't let her see you broken. Be strong, confident, happy. I know this sucks, but it isn't the end of the world or the end of your life. Use this time where she's angry to better yourself. And try to hear her out without defending yourself.
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt