When I have gotten sober in the past, the 5 to 7 months mark was my danger zone. After being clear headed and energized after quitting, depression and intense boredom would grip me and lead to a relapse. This time, realizing this, I'm trying to brace myself for the depression and hope I can maintain sobriety and push though it. I dunno, depression weakens me and, being an alcoholic, I know a drunken night will lift it --temporarily--but then I will almost certainly go into full relapse.
I'm rooting for you to hang in allow yourself to be depressed for a whille and not throw away all you have achieved. I believe for many long time drinkers, it is part of the healing process.
Depression is insidious and I have no advice how you should deal with it. Maybe you need to allow yourself to hole up for a while, do things you enjoy, exercise, take a vacation or see a doctor. I have planned to eliminate as much work stress as possible during this upcoming period. I have to accept that depression will disable me to an extent.
Best of luck.