Step 1: try to survive. Analyze your surroundings to know where to hide. Text your parents. Don't make a sound. Stay close to your peers.
Step 2: try to make it through the day. It's a weird day, but try not to focus on it. Death could be close.
Step 3: do your English classwork. I know it's weird and you're not in the mood, but just do it. It's the only normal thing.