Check the sight glass on the receiver/drier at the front of the enging compartment drivers side. If the freon level is low you will see bubles in the glass when the system is on. If it's low take it to a licenced qualified repair shop and let them fix the problem.
If the glass is full is your auxiliary fan or fans on? Is your heater control valve functioning properly. I'm Not even to the novice catagory guy..these are just a couple of things shared with me in the past. Good luck