Hello there, GlitterAndBlood. It seems like you're having a really rough time with your recovery. It's awful that you have to feel this way, and I understand that you're both hurt and confused about not being able to escape from these feelings. I wish I had an easy solution for you, but I don't. I don't know how to make it any easier. But maybe I can at least attempt to answer your question.
This is a very difficult question to answer. There can be any number of reasons why recovery can be really hard for certain people. It could be that perhaps you do not have the resources you actually need in order to make progress. Some people don't have access to medications or mental health services they require. Some don't have the linds of social support networks or people they can trust and who understand them. Sometimes there's just too much hurt, and it needs to be felt and lived through and dealt with before you can move on. Or it could be something else. You may not even be able to recognize a need that is not being met, and therefore unable to even begin to tru and fill it.
Another thing that can make recovery extremely difficult has to do with neural plasticity. Your brain is a double edged sword: it is capable of learning and changing and adapting, but it also really likes to stick to what it knows. The human psyche tends to cling to solutions that have worked for it before or provided some relief. And when those solutions are self-harm, there is a natural tendency to continue to do so once the behavior has solidified itself. And it's not just behaviors: thoughts work that way as well, our outlooks and mindsets. If we think of ourselves a certain way or see the world a certain way, that can become habit, and very difficult to escape from even when our circumstances change. We are creatures of pattern, and established patterns are very difficult to break.
It is also possible that there is something else underlying it all. Many people with mental health struggles, whether consciously or otherwise, internalize this idea that their suffering is somehow their own fault. They feel broken, worthless, or selfish. Some hate themselves for struggling or hurting in the first place, or for not being able to handle things or recover or be 'normal'. This is extremely common, and extremely hurtful and devastating. I can't say for sure from where I sit, but it feels to me from what you said that you may be blaming yourself for still struggling and not being able to get better. Don't. You are a human person, experiencing pain that you don't know how to process, trying to dig yourself out of a hole that you don't know how to escape. No one should be blamed for drowning, least of all by their own self.
The most important thing to remember here is in the title of your own post. Recovery is hard. It is hard. And it's going to be harder for some than others. You can't blame or crucify yourself for struggling. You can only keep trying to hold on, finding little ways to try and get through it as best you can.
And if you have to hurt yourself to make it through sometimes, then maybe that's what you need right now. It isn't ideal, but it's worth acknowledging when it's something you really need at the time, accepting that, and trying not to blame yourself for it. There is a kindness that you can do for yourself in allowing yourself that, and recognizing that it doesn't make you a bad person, or a failure, or a broken human being. It just makes you a person who is suffering, caught in a pattern of response that helps you to feel better for a bit, because that's what your brain has to work with right now. Perhaps that one kindness can go a little way to helping you find a way through this.
And if that fails, you have this community here. None of these people will judge you for what you're going through, and we'll all do our best to provide you with what you need to address these feelings and maybe get to a place where you can feel a little more at peace. Whatever form that takes.