I'm not an expert on non-succulent type plants as I used to over/under water all the time... but is the soil all the way dry? Was it wet for a while last time you watered it? When you water it does the plant perk up?But it was growing well in the same pot just a couple of months ago and had been since I got the plant couple months before that
Some of my outside vegetable plants looked sad and deflated like that this week. I was worried the soil had stayed wet for too long, even though I have a fancy soil that says it helps with under/over watering. I let the soil dry out almost to dry or was pretty dry, and the plants looked a little more withered at this point and more sad, so I decided to water again. The 3 plant pots that I did this with, perked up within a day and look much more healthy! Not sure if this is similar to your scenario, but wanted to share.
Do you fertilize it?