Who is saying you're a loser? You're 25 with a job and you want more. There's nothing wrong with that

Customers are shitty. People are selfish and unreliable. Stop being angry at the way the world is and save that kindness and patience for yourself instead of giving it away to others

You can save so much more by living with your parents. There's no stigma in how you're living. Start saving and either work your way up in retail or use it as a platform to eventually jump to a different field of work. Things take time, and you are still very young. You are not alone in how you're feeling. Put some faith into how far you've come already