Anne, I had also hear of using extra strength Vagisil for the discomfort down below, but when I asked my doctor about it he said that it could also cause other problems there and to avoid it if possible. Something to do with thinning and drying the tissues there, I believe. My slushy water bottles help a lot to relieve the pain cycles I'm experiencing with my PGAD.
Loulou, I really feel for you because I've been suffering intensely for more than a year now with my PGAD. This is my third bout of it. I look at it as 'the itch that can't be scratched' because I get little relief from orgasm. When I first had it and didn't know what it was, it made sense to try to relieve it, and at first I could get maybe three or four hours where it wasn't driving me outta my tree! Eventually the time between needing to find relief has decreased down to about 10-15 minutes, but I've also found that trying to get relief only exacerbates it..
It seems so cruel to get so many orgasms a day that do 'absolutely nothing' for me, give no relief, and drive me to distraction.. It's been a learning curve for me, but the more relief you seek, the more it aggravates it. I've found that either directly putting pressure on it (without rubbing it) or using the frozen water bottles to calm it down help quite a bit.
As I've made progress along the way, it was a big accomplishment to go from one day, to three days, to a week without 'scratching the itch' so to speak.. Now that my body has decided to add pain cycles to the mix, I find that trying to get any relief during them is extremely uncomfortable. Sometimes the pain cycles last more than a week, sometimes they're in conjunction with my period and sometimes not, so it is possible not to get the relief for two weeks or so.
I feel so bad for you that PGAD has affected your grades so much that you've had to quit schooling over it. Hang in there, try the pressure and icing techniques, try not to seek relief as often, and hopefully yours will become more of a 'background' distraction as opposed to something that runs your life.. It's difficult to get control over it but I have faith you can learn to cope with it better as time goes on.

On the road of discovery to see what is causing my PGAD.