Taken from an article by Archpriest Andrei Lorgus, translated by The Catalogue of Good Deeds

In my opinion, the experiences and complaints about the state in which sin literally haunts you and you can’t get rid of it can constitute a crisis of faith.  You just need to understand that such a crisis brings some spiritual benefit for you, enhances your knowledge, strengthens your skills, makes you stronger, and helps you move forward in your church life, as well as in your relationship with God. You should not panic and be discouraged in any way.

It is important to know that despondency (i.e. depression from the feeling that sins have crushed you) can mean that you need spiritual guidance. You face phenomena in your spiritual life, which you don’t always understand, and you need the advice of someone who can help you to know how to act in this situation. Of course, you can look for advice from people with spiritual experience, seek friendship with other believers who have a deeper and more serious background of spiritual life, life in the Church but for everyone their own parish priest is the best resource.

Another very effective inoculation against depression: do not think about whether you are a good Christian or not at this point. There are no better and worse people before God. That is why, when thinking about your sins, it is very important not to assume “God’s stance” and turn into a judge for yourself, biting yourself. Note what the Apostle Paul writes: “But with me it is a very small thing that I should be judged of you, or of man’s judgment: yea, I judge not mine own self. For I know nothing by myself; yet am I not hereby justified: but he that judgeth me is the Lord.” (1 Cor. 4:3-4).  Comparing yourself with other people, and even with saints, isn’t helpful. It only makes you hate yourself.

Finally, when thinking about a sin that you cannot overcome, you should try to figure out whether the sin is an independent and arbitrary event, or is caused by some other reason. You have to learn to know yourself. Sometimes certain passions or vices may be caused by factors that are not mystical and puzzling, but are related to our health, the mismanagement of relations at work, family conflicts, everyday circumstances of our lives, etc.

One more important point: it is crucial to set the right emphases in spiritual life. Being free from all sins is not an end in itself. The central goal of spiritual life is to develop a relationship with God, the communion with God. As you gain spiritual experience, you can overcome passions and sins. Therefore, focus on this most important goal: to be with God.

Furthermore, do not try to overcome all your sins and passions at once. Find the easiest sin that you can easily defeat — the passion that you can get rid of — and defeat it. The experience of defeating something easy will make you confident of your strength. Next, you have to take on something else but it has to be within your power. Do what you can do here and now. Can you get up early so you’re not late for work? Great! Will getting up a little early make it possible for you to read at least one prayer out of twelve? Excellent! Read this one prayer, and so on. Move step by step. Don’t be discouraged.