I agree with Mark - it's hard for any of us to say because it depends on alot of factors. I didn't do anything for the first week because I'm not young anymore and I figure better be safe than sorry. My heart was beating faster than normal while going through withdrawals and I didn't want to push it.
Regardless of whether you exercise or not, are you drinking plenty of water, taking vitamins, etc.? I read somewhere that it takes a good 3 days for your system to get rid of alcohol and even then there will be residual effects. So it might not hurt to take it slow (Like Norther said: take a walk, or something minimal?)