did i fry my pump?

Just run the pump till it begins to suck air Turn it off. Then look at the fresh water tank where the hose suction line is attached. Ignore the little lights.

Is the pump suction line at the water line? If so you have identified the problem, which is that your lights don't give you a proper indication, at least not with the trailer in it's current position. The solution is to continue to ignore the lights and just eyeball the tank level in future.

How I determined that there was 1/3 of a tank left when the pump started misbehaving is that water continued to come out of the drain for quite a while. Also the guage read1/3

How did you determined that you had 1/3 of a tank of fresh water in the tank (when the pump started misbehaving)?  Did you go out and visually check the tank (you can see the water level in the tank because the tank is an opaque plastic) or did you read what the gauges indicate?  If you read the fresh water level from the gauge then that is the problem.  None of the gauges are accurate, fresh water, black water, or gray water level indicators.  The drain line from the fresh water tank should be on the bottom front of the tank thus allowing 98% of the water in the tank to go to the water pump. After reviewing your stated symptoms I feel that there just wasn't water in the tank.  Don't rely on the gauges.  Hope this helps. 

Screen was real clean. It pumped like a champ once I put more water in it...no more sucking air or ugly sounding pp. So.... when I get somewhere suitable, I'll try readjusting the intake hose. Any more info appreciated

I would check the screen first, only takes a minute to unscrew and check.  Although it is possible, but not too likely, you may have the pickup hose in the FW tank that has pulled out a bit or was incorrectly installed in the first place.  A bit more involved but not impossible to pick up some slack and insert more of the hose so that it will draw all the water out of the FW tank.