Iván I also know how you feel. I think the best suggestion I can give is related to your interests and popularity. The town I live in, it seems that 80% of the jobs are .NET. I used to be a ColdFusion developer, but the company I worked at started to downsize. So I learned C#. I actually love the language now. But it was a big step making the professional transition.
I am now an iOS, Android and Node.js developer. I got real interested in mobile development when the iPhone came out in 2007. So I taught myself Objective-C. I am now learning Swift. It became enough of a passion for me to where I sought out a job doing iOS development fulltime, even though it is not a common discipline in the part of Florida where I work.
I think you will find in the course of your career that you will have to learn new languages and frameworks.
Be flexible and learn things.