Magdalena, I experienced similar emotions many times, especially in earlier years. Now I write more joyfully, with less thought of success or failure. Sometimes the words come easily and sometimes they don’t, but maybe in the struggle I seek God more earnestly. Nowadays I could sit down and write for an entire day as the hours slip by, so I have to discipline myself not to write rather than to write. There are other things God wants me to do, such as reach out to others, spend time with my family, read His word. So I force myself to stop, to focus on the various ways of servanthood He calls me to, and to use these experiences to nourish my writing when I return to it.
Your words are beautiful and it is such an accomplishment to learn to write in a language that is not your native tongue. Continue to proceed with joy and confidence, and let the results fall where they may, which means let them fall in God’s hands.