Go back; the WORST job at USAirways is better than the BEST job at AMR Eagle. USAirways will survive, and looks to be a great competitor in the future with low costs.
Your career is calling; you have to go. Its a MAJOR, scheduled airline job. You honestly think you'll be happy, even as an ERJ Captain, at a regional?
Oh, and better go back to US before the May deadline when arbitrator rules on seniority integration. If you're on the street, you may never get recalled.