Feel dumb asking, but Is this also an S trap?
Yes, it is.
The rule for P-traps is this:
The "trap weir" is the height of water where, if the trap is empty and you start dribbling water into the sink, water would first spill out of the u-bend into the rest of the drain system.
The "top of air" (a term I just made up) is the height of water at which, if you plugged the vertical sink drain in the wall and slowly filled up the system, the air space in the sink drain outside the wall would become separated by the water from the airspace in the vertical vent pipe (not shown in your drawing)
And the rule is that the top of air has to be higher than the trap weir. Otherwise, if the drain pipe outside the wall fills up with water, the trap can siphon.
Cheers, Wayne