Benny - since you have insurance and your boss is aware of your drinking issues, by all means do the detox. They'll give you the proper care to get through this with little pain.
As far as what to do right now..... that was a good choice cutting the grass since I felt so much better after a sweaty bike ride during my detox. I've also downed a lot of Gaterade, B12 and took Melatonin to help me sleep.
I know exactly how you're feeling as I've been there. I haven't hit the .3 with a DUI but came really close and I should have been dead a few times over.
Hang in there Benny and get on the phone tomorrow to see a doctor and what your options are. I wish I had that option a month ago during my detox, but I just did it on my own like I had times before.
Now at day 31 I feel great!
Good luck to you and please keep us posted.