Well done on being a month free, no matter what happens from now you have still achieved that and it's a step in the right direction.
I could relate to what you said first in your post, about being able to smile but really wanting to cry and so on. I'm sure many people have experienced it, please don't feel alone.
I guess what struck me, was that I would often become numb and also want to cut so I could "feel" something but really, it isn't a positive thing to feel and it isn't going to help. In time, when you aren't cutting anymore you will begin to feel new, much more wonderful things. Maybe you haven't had that experience yet but you're still fragile and still learning things, it will get there and for me certainly, it was better than the feeling of cutting.
It must be scary knowing how close you came to self harming but a massive well done to you because you didn't cut. You had the blade, you had the oppurtunity but you made the decision not to harm yourself and that is a huge step to take and a very determined decision. You can keep doing it, again & again. You have control now, not the self harm. This is your life, not a life revolving around self harm.
Would you feel able to discard of any thing you can hurt yourself with? It can be a huge step and just means you have extra time to think if you want to hurt yourself because you won't have anything to hurt yourself with. Some people don't find it possible to discard of their tools and that's perfectly understandable but it is an option which you might want to consider.
I think you need some serious TLC, to reward yourself and treat yourself a little. Do something lovely for yourself, like having a hot bath with lots of bubbles or taking a walk out in the morning on a nice day when it's crisp and gorgeous. Go to the cinema or go out with friends. Even just reading a book or magazine you enjoy, just something for you.