2000 classic xl a/c

I have a 2000 classic with a/c problems When it blows cold it will run you out,But then sometimes it blows hot air when this happens the compresser kicks in and out and the and the high side goes through the roof. When its working the low side is around 35 and the high side is around 200.Ive cleaned and looked at all the normal things with no luck. Thank you for all and any advice.