Ask for the Zwischenzeugnis, your employer is obliged to make you one.

It might be a wise decision to be quiet about your job search for now. However this depends a bit on your situation. A friend of mine dropped the bomb (among the lines: "I need this and that afternoon off" - "Why?" - "applications at your competitors") and his salary was increased on the spot. But he had been underpaid and the company could afford it, I don't say this works always!