Typically when you use the gauges, they only prove there is freon in the system when the compressor is running. One side is the high pressure side and the other is the low pressure side. It sounds like the compressor stopped running. Any number of things can cause this, the most common being low freon. I would start by adding just a small amount, about one half pound and see if the compressor comes on. If it does, then you know you have a small leak someplace. When the pressure gets to high or to low, the pressure switch will prevent the compressor from running.
Also, make sure both cooling fans are coming on when the a/c is on. If not, the hot freon will develop to much pressure and the system will shut down.
Finding a leak without the use of dye and a black light is very difficult, especially if the leak is a small one, one that takes 10 yrs to allow enough froen out to lower the pressure enough so that the compressor won't work. You will need dye and a black light to find it.
Please let me know what more I can do to assist you today. Also, please remember to rate my answer, Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, or have a subscription a rating is still required.
Thank you so much!