Moving at the speed of light stands for life racing ahead, events happening faster than you can take them in. Tradition reads it as thrill or overwhelm, depending on how the dream felt.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.