^ That's good advice, although I think some cases of liver damage have been reported due to valerian use - probably not an issue if you have a healthy liver, but three years of heavy alcohol abuse might have lead to damage in some form. I don't know an awful lot about valerian though, so correct me if I'm wrong about that. I agree to definately taper, particularly if you're not going to see a GP about this - but I would highly recommend you do. You've been drinking dangerously large amounts over a long time and stopping cold turkey is risky.
www.alcoholism.about.com has some info on what you can expect during withdrawal, as well as various treatment options (if you live in the US). If you're not American, it'll still give you an idea of the methods avaiable to you - support groups, rehab centres, pharmacological treatment, counselling and so on.
I think you should focus on two things at this point:
1. See a doctor to determine how dangerous it would be for you to stop. This will help you decide whether you need medical treatment, whether you should seek an inpatient rehab, whether you can deal with withdrawal on an outpatient basis, etc. Long-term alcoholics also usually have some serious vitamin and mineral deficiencies (among other health problems), so getting some info on this as well as a general health check would be a good idea.
2. Get counselling or therapy to deal with your underlying anxiety and panic issues. You'll be very lucky if you don't find withdrawal stressful and a cause of increased anxiety, and learning some ways to deal with this is a crucial part of resisting the temptation to drink more. Be wary of the temptation to just keep increasing your benzo intake to deal with the anxiety, too - benzo withdrawal is easily as dangerous as alcohol withdrawal and can be far more unpleasant to go through.
Hopefully you've got people (friends, family) to support you in your desire to quit. If you don't, seek out some. There are many support groups available, particularly if AA is your sort of thing. Good luck.