Excessive A/T Shifting?

Hey guys, I have a 1999 Honda Accord EX-V6. This morning on my way to work, I noticed that I was shifting into 3rd a LOT more than I typically had. I have to drive through a portion of West Virginia on my commute, so I drive over a lot of hills and I usually don't experience a lot of shifting. However, this morning, it seemed like every single hill I was going up, the tranny would shift. On the get-go, I've also noticed that it doesn't seem as powerful.

Any suggestions? Trasmission flush? Tune-up? Anyone else with this problem?