How to deal with blocks, when they are coming?

How to deal with blocks, when they are coming? Hello. Today I had to speak before few people, I didn't have any kind of anxiety, nor worries, no nothing. I thought that I will be able to be fluent, but I wasn't. I had many blocks, and many I missed air. The words didn't come out. I had many blocks. My questions are; How to react when blocks are coming? How to deal with blocks? Maybe some advice for speaking in public? It's really annoying having blocks.