A "head full of bees" is an expression used to describe someone who is acting in a scatterbrained or erratic manner. There are many synonyms for this term, including "spaced out," "scatterbrained," "flighty," and "distracted." Other options include "absent-minded," "confused," "disorganized," and "lacking focus." If you're looking for a more playful or humorous term, you might describe someone as having a "hamster wheel for a brain," or "having their head in the clouds." However you choose to describe it, having a head full of bees can make it hard to concentrate and stay on task, so it's important to find ways to regain your focus and stay grounded.