I feel ya, man. For the past couple weeks I put my training on hiatus (got bored with it, which is a terrible reason, but meh), and now that I have picked up running and bag work again, I'm amazed at how much it's killed my endurance (even though I'm still the lightest weight I've been in years, I used to be able to go for 6 or 7 2-min rounds at a time on my 70lb bag, now I seem to get winded just walking down stairs to it...). I can't imagine working off 6 months...
My deepest sympathies...