I think taking on responsibility for your own independence, as others have suggested is the best route. Show instead of tell. (?bike to work, public transit? co-worker, other), start to save a percentage of your pay, no matter how little each week (start a savings acct. if you do not have one); choose something to do to help out at home (if you already don't---) & do consider paying a minimal rent.
It sounds like you need/want something quite normal, for mom to express love and confidence in you---for whatever reason, this is not something she is able to do right now. You can only change what you do...
This will pass. It is not an easy time of life.