I am sorry you feel that way. I think you just need to stop and think and slow down. Look at all of your achievements and how far you have come and be proud of those first, then set higher goals for yourself. You need to live life one day at a time and quit thinking about the future b/c it is making you depressed it seems. You should feel good about yourself, you are working in a high company and you can buy expensive designer bags. It seems you are focusing too much on how to improve things rather than focusing how good you actually have it, things could be worse. If you aren't happy where you are working, I would stop and think about what is making you unhappy and go from there, even if it means getting a new job would get you happiness(this is my opinion
Just slow down and give some time to yourself. Look at how far you came and find pride within yourself.
Be happy.