Hey Mike:
Well welcome back friend! Slips happen. It happened to me too when my sobriety was not my priority. And I did it at a wedding as well. I was Best Man and had to make a toast with Champagne. Had 6 years clean and from that night on, sixteen more years downhill. I wasn't done with my drinking yet it appears. I can so relate.
I live in the moment today, on life's terms, not mine. AA has really helped me. I apply its' simple principles to my life whenever and wherever I can. You didn't mention being involved with AA but you mentioned you had 4 years of sobriety.
That, in and of itself, is an amazing accomplishment.
Okay, so now we're on day one and we're feeling those horrid feelings of resentment and fear. Brother, I can promise you it gets so much better from here on out if you just don't pick up that first drink. I recommend a plan of recovery, a living plan of recovery, albeit a simple one. We're in this boat together, Brother.
Think about hitting an AA meeting asap (like today) in your vicinity.
All I can suggest is what is working for me, so please keep coming back.
Hang in ther, Bro.
Tallone