You can learn from everything man...
This. Not sure if you were certain that you were unable to control your use, but if you had a desire to quit and used again, then this is an excellent experience. Though it may not feel like it, this relapse may knock that last little bit of doubt away, allowing you to pursue a thorough recovery with no nagging suspicion that you may be able to control drugs next time you pick up. If the illusion of control has not yet been smashed, perhaps it may be wise to experiment with some controlled use. The first step in recovery is admitting that you are powerless, and if you don't believe you're powerless, how are you going to recover? Anyways, this whole paragraph was written with the assumption that the first step was not completed. My apologies if I am incorrect.
So, if you know you can't control your use, and want to stop, good news: there is a solution. I know only a little about other options for recovery, but I can say with certainty that 12 step recovery will work if you are willing to do the work. Not a 12 step fan? I find it useful to apply a utilitarian perspective; the end result is freedom from drugs and peace of mind, so why does it matter what it takes to get there? Once freedom and serenity are obtained, you are in a better position to examine whether the ends justify the means. Anyways, about the solution, that comes from doing a thorough fifth step with a sponsor. After the fifth step is completed,
the desire to use is lost. Completely gone. If you haven't done a fifth step, how the hell could you have stopped using for even a day? Untreated addiction is pure torture. Some of the most successful sponsors I know in Alcoholics Anonymous (a 12 step fellowship) believe you can keep using until the fifth step is completed.
If you have completed a fifth step, had you finished making amends? Had you continued to take personal inventory? Had you spent a little bit of time each day defining and constructing goals in life? Had you helped others find a solution to the pain and suffering in their lives? Were you working toward a sexual ideal? It may also be useful to avoid situations/ people with drugs until you are stable in recovery. This is not to say stay away for good, just until you have a solution. I still spend time with friends I used to use with and go to Dead shows as often as I can (read pages 100-101 in the Big Book of Alcoholics Anonymous for more information).
Anyways, hope things get better for you, please PM me for info on how to get hooked into a solid program of recovery, it's a shame I didn't join BL a few days earlier while I was in San Diego going to NA meetings all over the area. Everything will work out though. The first sponsee I ever had complete a fifth step was cutting his wrists every few days until we did his fifth step, since then he hasn't taken anything and is happier than I have seen him before (not cutting anymore either). Try to keep in mind that life
will get better- so long as you stop fighting.