When did you plant it?

If rather recently, stick your finger into the top surface of the rootball. Likely it's dry.

Evenly moist soil is what camellias like. Periods of dry and wet and dry again are not good. Eventually, the root ball starts to repel water instead of absorb it, the rootball starts to shut down and you need to extract the plant and dunk it in a pail full of water for an hour or so until you do not see any more air bubbles. Alternatively, you can set a drip irrigation-like set up with a hose; basically provide water at very slow levels of a drip every second or slower so the root ball moistens again because just watering with a hose as usual will not make it absorb the water. If you decide to extract it, make sure that the roots are not circling like they sometimes do in pots; if they are, cut them vertically every 1 or 2".

I would also recommend using 3-4" of pine needles, pine straw, shredded leaves or shredded small to medium bark mulch, shredded cypress mulch, hardwood mulch, etc. Rocky mulch gets hot in the summer months and that is not good for camellia plants that like a lot of water so if you can afford it, try the other mulches. The change in mulch can be done before next summer as temps will now be lower and stay cool thru Winter and most Spring.