You do deserve a good job
It sounds to me like you really want this. I don't think you're worthless but I know that no matter what it is that I say, that doesn't always take that feeling away (trust me!). Instead of focusing on getting accepted into a private sector maybe right now, you can consider finding a part or full time job at a restaurant or grocery store. You seem so passionate about getting a good job so just hear me out. This way, you can make your own money without asking your mom for any.
I'm suggesting this because you seem clear that a job would fix everything for you (which is awesome to hear) and this could help you with feeling more independent and changing how you see yourself. While you're working and making your own money, you can always revisit looking for the job that you dream of. I think if you know that you're making your own money then maybe you would feel slightly better about this.
I know that this isn't as easy as I'm making it out to be. I'm not looking to solve what it is that you're going through because if it was that easy, I know you'd be able to do it yourself. I'm offering you advice and if there's anything that I want you to take away from this it's that there's no timeline on life. Even when all of this does make you feel sad, remind yourself that you accomplished something awesome -- you experienced university.