Hi there,
The important thing you have to remember about recovery is that it isn't quite that simple. It's hard and painful, and there's going to be bumps along the way, but the best thing you can do is to stand up and move forward if you've fallen. I'd be surprised if anyone recovered without relapsing.
As others have said already, you haven't failed anyone - and I mean that. Please don't beat yourself up over it. There are lots of alternatives to cutting, some of which are already listed on both the
TH website and in this thread. An alternative might work for one person, but might not for another person, so try to persevere and find the one that really works for you.