'99 Civic A/C troubleshoot

My wife's Civic has been blowing less than cool air lately. It seems to be worse when at a stop, so I thought it might be the fan, but in my garage, when the A/C is on full, the fan comes on. So:

I checked the Freon pressure in the "Low valve" and it was a little low, approx. 30, when it should have read 45-55. I added freon, and all seemed well (though I never could seem to get the pressure guage to read the appropriate pressure) ; air was cold, wife stopped complaining, etc. For one night.

The next day it was noticed that the engined felt like it was surging/getting power drawn, only when A/C is on. That was yesterday.

This morning, the A/C was not blowing cold air at all. My wife said she does not hear the A/C turn on, or draw power when turned on, and no surging is occurring. Does anyone have any ideas? I gotta cool the temper of my wife down!

Is it possible it is as simple as a fuse? Or, do I have a leak and need to go to a mechanic? I would love to solve this one. Thanks for any help!

Aaron

Just spoke to my wife, who neglected to mention there was a high pitched noise happening last night. Not sure if this helps in any diagnoses.

Thanks again!

kinda sounds like maybe the pump is starting to seeze up. if its not turning on you either have no r-134a refrigerant or your pump/ clutch its done. check to make sure it spins somewhat freely and make sure your belts are tight. i would recommend have a technician do and evacuation and leak down test on it to make sure your not leaking all your refrigerant out.