"persistent, stinging loneliness"
I vividly remember that phase of my life. I would not want to live it again. It was a combination of shyness, geekiness, being a foreigner in a new land and persistent rejection arising out of the first 3. In hindsight, the big mistake I made was to try to fish in over-fished waters (typical engineering graduate school, where every female has numerous suitors). There exist overstocked ponds, demographically speaking, where you will have much better luck. School teachers, nurses and the like come to mind, but there are many other demographics. The school teacher demographic is a good one: they tend to be bright and idealistic (and many of them are pretty too!).
The good news: I eventually came out of that phase, got on with life, found a wonderful woman (my wife now), and even made decent money ... so there is light at the end of the tunnel. If I can do it, you can do it too.