How to get into econ/finance/maths after engineering?

You have already made a good start in business type things, and you successfully completed one of the most difficult under graduate curriculums. Your resume should look good. You don't need more full time college, in my opinion. With sufficient self motivation you can learn most any of that easier than engineering stuff, on your own with the help of a good mentor. If those college professors really knew how to make money, most of them would be doing it instead of teaching. Much the same for engineering professors who do very little real world engineering, which likely is why you are depressed about engineering. When you go for job interviews, think positive, even if the recruiters description gives you a head ache. My 100 jobs were all almost totally different than what the recruiter and human resource people told me. If it doesn't kill you, it will make you stronger. Unless you already speak German, Germany will be depressing. My wife, who was more successful than I, says " accept any job you can get. Learn about your bosses job with enthusiasm, while you take a college course or two on your own time" You can tell the human resources people that you intend to learn your bosses job, but you should likely keep a low profile with your boss. Neil