Dreaming that you are moving more slowly than usual or can barely move might mean:
You're feeling slowed down or restricted somehow in your life
You feeling certain physical sensations while you're asleep (such as your leg being asleep)
Dreaming that you're trying to run away but can only move very slowly might mean:
Your subconscious mind is creating a worst-case "what if" scenario
You could be having a Toxic Dream