Should I repot my Easy Bud by RQS, I'm 5 and a half weeks in and she's looking very small and growth seems to have slowed down?

At 5 and a half weeks in, you should be right before or right after the stretch. With my autos, they came to a grinding halt 3 days before the stretch and then exploded. If its right after the stretch, you should expect the growth to slow down. During the stretch, they will almost double in size, growing 1-3 inches daily. Repotting this late in the game is probably a big no no. Hopefully you're in at least 3gal pots. It will become root bound in a pot this size or smaller, but it should be able to finish without problems. You will just have a smaller yield. If you're in 5gal or bigger, it will reach close to its maximum potential as an auto. Hope this helps, good luck!