I remember thinking that way more times than I can count.
You are not a failure. This may merely by an indication that what you are trying to stay sober over the "hump" needs some re-examining. Try something different, try and identify your triggers. For me it was over-excitement. So for the up-hill period, which is different for everyone and can recur after days, weeks and even months of smooth sailing, I tried to keep that sort of stimulation within limits.
The fact that you are here and not giving up is powerful testimony that you are not a failure.
And besides, failure tells you one thing and one thing only. Try again.
Fear, however, tells you "don't even bother trying." I choose failure over fear. How about you?