Well you can afford to be sad, no problem, but that doesn't detract from the 5 months sober you achieved.
So why did you drink? You need to know, and that's an answer only you can honestly give. I had a great counsellor years and years ago, amazing guy., and he would say to me, when i got 5 months sober and drank again that it is much better than the 24 hours and drink again that you had before! Don't beat yourself up, eat well, get some sleep. Your new 5 months is going to include a personal self discovery of why you drink, that will keep you protected from taking that first one. You are doing great.