There could be several different issues that could cause your concern. First, while running your A/C, carefully touch the low pressure (larger) A/C line and sense its temperature. It should feel cold while the compressor is engaged. If the compressor does not engage or the line does not feel cold to the touch, a refrigerant pressure issue may be a problem. If the low pressure line is cold to the touch, the issue may be with a air distribution system. A blend door under the dash may not be directing air properly ie the heater core may be exposed blowing warm air into the refrigerated air.