The problem could be below the surface, something chomping at the roots.

maybe too dry....I had to give mine a good soak this evening.

If you mean Phlox paniculata, its probably drought, as Johnp58 suggests - these are very thirsty plants, flopping and drooping the instant there's a bit of dryness in the soil. Water well...

I agree with Bamboo. My phlox ( in a pot) need watering every day or they they start to droop.