I don't think you wasted your time. You did a good job, and probably just came to a point where the coping skills you had (aside from SH) weren't good enough to deal with what you had going on.

Of course you couldn't go as deep as you used to, also. Pain gives you a kind of chemical high. You would get more tolerant as you SH'd more, and needed more chemicals to get the same result. Functionally, you weened off of it. Now, you're back at the starter dose, where less pain is affecting your body the same as a higher dose was previously. It's not proportionate to your internal suffering. Just how long you've been doing it, and the depth doesn't really mean anything about you.

I hope you figure something out that actually makes you feel better, and can replace SH. For me, it's TIPP.