Hey Kekkoa, I'm sorry to hear that you're going through such a difficult time right now. I've found myself thinking in similar ways in the past, and it's terrible. Many of the people who want to help can't, because they cannot imagine how difficult it is to do things without motivation.
When you are at your most depressed (ie suicidal), your motivation is at it's lowest (because at it's core that's what depression really is. Most of the other bad stuff is just the result of having a lack of motivation).
I don't know the specifics of the challenges you face, but it might be possible that you can't help yourself, at least not directly. It might be the case that the only way for you to help yourself is to see a therapist, so you can be helped by someone who is experienced in treating people with suicidal thoughts. I suggest you use whatever motivation you have to go see one, use everything you have left to get there.
The funny thing about motivation and depression is you gain momentum exponentially. Once you start finding what works for you, you will have more energy to help yourself get better, and it continues on like that until you are better.
You could also try reading a book on cognitive behavioural therapy as well, reading is a relatively low effort way of helping yourself. CBT aims to challenge negative assumptions and thoughts, and come up with more balanced and reasonable alternatives (not necessarily positive). For example, you say you can't do anything right, is obviously a negative belief, but it's not true for you, or any other person for that matter. A more balanced alternative could be something like "I'm not good at many of the things that matter to me, but I have excellent spelling/grammar skills, I can make an great grilled cheese, I'm kind, and good with animals...etc". It might surprise you how making subtle tweaks to your thinking can improve your life. Challenge your negative thinking!
You've probably experienced a lot of setbacks and disappointments, so I can understand if you're feeling suicidal. When I was suicidal, I would not have believed how good my life would be not even a year later. There was literally, no way you could have convinced me it was going to happen, and I'm not here to tell you that it's going to happen. I just want you to believe it's possible. No matter how unlikely it seems when depression is lying to you, telling you it won't happen, remember that it's possible.
Are there any specific problems you want to talk about? I'm sure someone on the forum will be able to relate to you and possibly help you out.