USB connection unreliable while tethering
I faced similar lost internet connection issues with galaxy y tethering. Had to unplug and plug in the cable; again select tethering. However, i noticed that orientation of the cable just outside the socket mattered. There is room for movement even after usb is plugged in the phone. In this instance, when i so arranged that the usb cable is as lateral as possible to the phone midline(had to use anatomy); there was no lost connection.