Perhaps your Mum is trying the 'cruel to be kind' / 'tough love' route, mate. She loves and cares for you, she wouldn't have had you back at in the 1st place if that wasn't the case.
Sometimes we all need an arm around the shoulder, telling us that everything is going to be alright and other times we all need a kick up the arse. Most of us naturally procrastinate and make excuses not to do important things that we know we really should do. If we're left to our own devices, those excuses start to feel valid to us and a sharp dose of reality from a third party, although painful at first, can be very good at snapping us out of our comfort zone.
It's how you react to that from here that's important. Despite what you may think, you are not weak and you are not poison. You're a good person and you have a lot to offer the world. Hear what your Mum has to say because she knows you better than most, those words will hurt but they won't break you. You're strong and you can take it, I know you can.
A job and a flat seems a world away right now but they could be just what you need to turn things around. The way you're feeling is totally understandable but things are never as bad as they seem. It's important to stay positive mentally but it's even more important to keep making those positive steps we've talked about. We're all here for you mate.