The False Promise

I recently told my friend Sarah that I would help her move next weekend. But honestly, I was looking forward to going on a camping trip with my partner instead. As soon as the words left my mouth, I regretted it because I know how much she needs the extra hands. Part of me wonders if there's a way out without being completely rude, but another part feels guilty about lying in the first place. Maybe I should just be honest and find someone else to help her, or is that too selfish? It’s confusing to weigh my desires against what feels right for my friend.