Yochid,
The response below is copied from chizuk email #461. I thought you might find it helpful:
....You may indeed feel like you're starting all over, but you really are right where you left off. Let me explain:
The Vilna Goan asks how a person can know what their purpose for coming to this world is. How are we to know what our most intimate and personal challenge is; i.e. the very reason for our creation? The Vilna Goan answers that we can know this by seeing what areas are most difficult for us to control, and what issues challenge us most frequently. It is for those areas that we were sent to the world to fix.
So Ari, if this struggle is a major issue in your life, it is likely that this is your own personal Tikkun in this world. And if this is one of the main issues you came down to the world to fix, it stands to reason that you may have to spend a long time in this struggle. But how? Once you've made good progress, what is there left for you to do?
So what Hashem often does, is that precisely when we have made serious strides, our successes are taken away from us and saved in our spiritual "bank" so that we can start over again from scratch and earn yet another powerful "spiritual" coin in the struggle. And that is why the old excitement disappears, the same struggles come back and it seems that we are starting all over again.
But Ari, when we have enough coins, we will finally have fixed what we came down to the world to do! And when this happens, Hashem will save us from this struggle forever.
So don't be discouraged, this can take sometimes years. You are not back to square one as it seems. But rather, as you said, you are "right where you left off". You may be only one step away from the finish line, but for that one step to be a decisive step, Hashem makes it appear again as if you are just starting out.
It is brought down in the sefer menucha v'kedusha, written by a talmid of R' Chaim Volozhin, that even a person who sins his whole life can still be considered a Tzaddik, as long as he never gives up and always continues to fight. We like to think of success in terms of results. But Hashem looks at our efforts, not the results!
And that's the ultimate test:
Hashem wants to see if we only take steps when we feel are getting somewhere. But a real warrior understands that Hashem doesn't care that much for the "results". Rather, it is little steps we take each day - the new Hischazkus that we have to keep summoning anew - that truly give Hashem pleasure and make us into Tzadikim.