I personally had a writer's block last year, due to the death of my mother. I was 15 days without writing, because I always remembered her, and thoughts came and went.
Writer's block exists, but is not a rule. It may appear or not. This will depend on your state of stress, emotional, health problems, excessive perfectionism, fear, frustration, ingestion of alcoholic beverages, use of illicit drugs, among others.
This article is amazing, and can answer all your questions:
Don´t be afraid and good luck in your writing career!