Hi
I did the same thing, I hadn't self-harmed in over a year and then I did it once and now I do it occasionally.
I'd suggest getting rid of anything that you use to harm yourself, if that's possible, and telling somebody so that they can hold you accountable and help you to not do it.
Its a coping mechanism so I'd also suggest you go for counseling to help you deal with your problems in a more constructive way.
i have self harmed have you had treatment for depression i find i seem to do it when i get stressed is any thing too much for you at the moment
the longest time I haven't hurt myself when I began in high school is six months, Doing something has mostly helped me such as baking, finding a movie or show, or my friends. Also as tracyb80 said get rid of the things you use to hurt your self if you can, some of the things I use are part of the house or my own two hands but A year ago I got rid of my razors, It helped untill I found more creative ways to harm myself. I also found that for some people talking about selfharm is also helpful, some of us can relieve those times and realize in one way or another that they don't have to do it any more.