Try some epoxy resin, like Araldite.
When I was in Ireland I discovered that the thread had sripped in my BB. There was still somethread there, but my BB kept working it's way out.
I limped to a town and bought some epoxy resin and glued it in place, ate in a cafe to bide some time to allow it to set a bit, then rode back to the hostel, carefully.
It did at least another 1000 miles, no trouble. The frame has since been scrapped (It was in a bad way) but it would have probably held up for plenty more miles.
Either way, you might as well get another frame and save yourself time, money and hassle. Having a bike you can rely on saves money on train fares home when an unreliable bike breaks. Plus, you's still need to buy another reliable bike on top of having to pay to get home.
Have a nice new bike, save yourself some money and have a nicer ride instead of flogging a dead horse.