Honestly, even though we're only getting one side of this there's only a couple of rational paths forward.
- Definitely don't just close your eyes and keep going forward with the wedding. Shit isn't right and a wedding isn't a cure for relationship problems.
- Couples therapy CAN work but the more I look into it, the less stock I put into it. Think to yourself if you can live with this person for the months required to do the therapy (not to mention potential costs associated with it)
- Consider your motivations for staying. If it's just loyalty or fear of not finding someone else, leave. If it's something akin to love, maybe consider roughing it out a short while longer.
People change, and it's very possible that this girl is not the person you got together with anymore. BUT it is also possible that her depression is playing hell with her not having a job and feelings of guilt for how tough things are. Her behaviour could have an understandable root cause.
Your call, man.
Personally, I think she's acting like a damn child and not worth your time. Plenty of women out there especially if you're still young and hale.