My engine feels like it's going to die when I have the air conditioning running

Hello, the air conditioning system can indeed put stress and load on your engine. There could be a few things going on here. First, your compressor could be binding and causing excessive drag on the engine and accessory drive. If this is the case, the compressor itself will need attention. Second, your engine performance could be at fault -- fuel, spark, air or some combination of those having a concern, where any additional drag on the engine enhances the symptoms that are maybe already there but not as exaggerated until a load is put on. Hands on testing is needed to figure out what is happening.