Feeling trapped!

One of the worst feelings of my career as a software developer was at the four year anniversary of my first job. The company is a software company whose future was in doubt. Layoffs always seemed to be a looming reality and better times seemed like they were a thing of the past. My mentor, and manager, left for another company and I was left supporting the work that my team had done.
It didn't take long for me to get tired of supporting the software. Frequently, issues with the highest levels of visibility would come in and I would need to dedicate my time to addressing those issues. According to the metrics that were used to evaluate me, I was underperforming. I received no credit for resolving critical issues, yet I was criticized for not meeting deadlines for the issues that were displaced by the criticals.
What scared me most is that the expertise that I was developing applied mostly to the domain of the software that my company developed. The only really interested company was one that did consulting on the software that I wanted to get away from.
Other businesses wouldn't take a chance on me. It was very painful for me to come in to interviews and be told that I didn't have the skills they wanted. To me, I heard you're not good enough to work for us.
Some of the people were more polite than others. Some were not very nice at all. In retrospect, it was probably a better thing for me that I wasn't able to get a job then.
At the time though, I was a mess. Unless you've been in this position of not enjoying your work and feeling that you don't have alternatives, it's horrible. There's hope though. I was able to get out of that position.
spent my weekends learning the technologies that businesses are using and making myself a marketable developer. I took jobs that would build on those skills. I am confident that I could easily take a job with a number of other companies if I needed to.
Even when I have days that are not very enjoyable, I don't feel trapped. It's amazing what options can do for an attitude.