NEED HELP ASAP

I have a 2002 Ford Focus LX Well the AC stopped working a year ago and now it stopped again, See it worked in my car then i went shopping came out it worked then it didn?t feel that Cold. Now it blows nothing but hot air. what could be the problem? last year i had the compressor replaced and some hoses and i can?t remember what else. What could be the problem now????????????? HELP PLEASE!!!!!!!!!!!!! I really dont understand how this is happening when it was just fixed a year ago. ARGHHHHHHHHHHH