a/c on 02 chevy s-10

I have a 2002 chevy s-10, its a 4cyl and has like 62000 miles. the a/c on it is dead. it used to work great. one day i was out, it was working, i parked it for 2hrs, got back in it and it wasnt working very good, parked it again and it was completely gone after that. i thought it had a leak but a friend of mine check and sit its almost completely charged. but the readings he was getting was 150 on the high and low side. i hate to think the compressor is bad already after 5 years and its been babied. anyone have any other possibilities maybe?? please help

orifice tube? Isnt that what makes the change from the low to high? if he was getting equal readings then maybe thats leaking? I dont really know much about a/c but i believe that is the part that makes the change, and its like a 3 dollar part.