Please listen to this great shiur by Rabbi Shafier that he recently recorded for our members called "Guilt & Teshuvah".
Please realize that although the Torah takes a tough stance when we don't listen to Hashem, however Teshuvah was created even before the world was created! Hashem knew that we would stumble in these areas. He has infinite patience and He understands us far better than we understand ourselves. Chazal say that Hashem even brought David Hamelech to stumble with Bas Sheva, only to show us the incredible power of Teshuvah.
Also, it is brought down in the Holy books that, through a sincere Teshuvah, all the souls that we created through our sins actually become uplifted, and they change from being “accusing angels” to “defending angels” instead.
So never despair! Although the standard Teshuvah model may not always work well when dealing with these addictive behaviors (On GYE we help people see that they are not "bad" but rather "sick" - or you can call it addicted), by learning the proper perspective on this struggle and by taking the steps we can to break free, we are doing exactly what Hashem intended for us to do all along. That is our Teshuvah.
Take this iron-clad rule: If you do what you think Hashem wants, and you really mean it sincerely, you will never be harmed. The Pasuk says: “In all your ways you shall know Hashem, and he will straighten out your path for you”. Chaza"l say: “Hashem did not give the Torah to angels” and they also say: “Hakadosh Baruch Hu does not come and try harassing his creations [giving them tasks that are too hard]”.
Also, keep in mind that the past is out of our hands. All Hashem asks of us is the NOW. If we learn from our falls and start taking real steps to prevent them in the future and work on our recovery NOW, we are doing real Teshuva and making Hashem happy.
So keep up the good work and keep moving!