Hello there, nance. It sounds like you're in a pretty rough spot right now. Sadly, I'm not God, so I don't know if I'm really qualified to be offering advice on this. That said, I'm definitely willing to try.
first off, I totally get how painful it can be to feel like you're not doing enough for the people you love, especially when they have real problems that you feel you should be trying to solve. I've been there, and I felt worthless too. It's awful. And I get that you love your mom, and you feel like you need to make things better for her sake. I've been there too. But as disappointed as you may feel in yourself for not doing more to change your family's financial situation, you're not a monster, and you're not useless. Moreover, fixing your family's financial crisis should never have been your burden in the first place.
Let's be clear about one thing here: you were a child. Or, if not, a young adult at most. Your place in this world wasn't to solve your parents' problems. It was simply to exist, to grow and to learn so that one day you could build a life for yourself. Your own life, every bit as worthy as your mother's or your father's. That's what any loving parent wants their child to focus on, not the burdens of the last generation.
And deep down, we all know this. Maybe not consciously, not in a way we think about and plan for, but our bodies know it. We are self-interested creatures; we can only really give of ourselves past a certain point once we ourselves are taken care of, regardless of whether we want to or not. So when you tried to confront a problem that was much bigger than you, that you were not prepared for and couldn't possibly be expected to handle, your body shut down. It made you feel weak and tired and helpless. Confronted with the possibility of breaking yourself at a young age on an insurmountable problem that was not yours to bear, it chose the dates and the zombie internet. Your psyche did that to protect you.
So what happened next? You got stuck. Locked in place, unable to really make any progress or develop any skills. But I don't think you're useless, or lazy. I imagine you probably had things you wanted to do, activities you wanted to engage in, but I'd also imagine you probably felt guilty about that. After all, if you had the energy to live your own life, to do things and to grow, then you'd also have energy to throw at the 'problem'. And since you couldn't seem to do that, I'd be willing to bet you probably feel on some level like you don't have the right to do anything else either. It's easier to do nothing, become an internet zombie, because at least then it doesn't feel like you're doing something else with your energy that isn't helping your mom. This may even still be the case.
A great many young people tend to crucify themselves for not being able to fix their parents' lives, and think themselves monsters for being more interested in just existing for themselves. But that's the way it should be. You're supposed to be going on dates, wasting time on the internet, and making dumb choices that don't land you a job or a skillset. That's the way this all works. Expecting more than that out of yourself, when you were never in a position to be able to provide it, is just being unfairly cruel to your own person.
You can love your mother. You can even try to make things better for her, in what capacity you can. You can offer her your support and companionship, be someone she can talk to and lean on when things get hard. But you have to live your own life too, be your own person, and do even that at your own pace. And you can't if you're too busy trying to carry the burden of such a heavy expectation of yourself. You don't have to flame achieved anything by now in order to deserve happiness and your own space in the world.