Any time my clownfish have ever laid up against the panels, egg crate dividers, or anything else in tank; it has been them just trying to sleep. Maybe your fish was trying to rest being that it was 4AM, and I'm assuming your lights had been off at least since midnight.
Clownfish act weird for the first few days after bringing them home, and it laying on the sand bed like that seems to be it being stressed from transport. What was your acclimation process like?
If you don't have any corals to keep alive, trying lowering the water flow, oxygenate the tank a bit more, give it some hideouts, and leave the lights off for a while. Try feeding it just a tiny bit to see if it eats, but don't trash your tank if it refuses. Using Garlic Guard has helped me get new fish to eat after a day or two of failed attempts. Check your water parameters to make sure everything is where it's supposed to be.
It could also be tank mates harassing it, so watch out for that—frayed fins, panting, staying stuck up in one corner for too long, or trying to jump out are among some of the signs.
Hope that helps a bit.