I absolutely understand you. Using public transport sux. I am in exact same situation, just had my bottom bracket broken. And I ride bike everyday. Now a car, bus or walking... neither is a good choice.

Have you considered using thorn resistant tubes?

I used to have constant flats as well, until these tubes, that never yet had a flat and it's over a year now.
I also put several layers of electric tape on the inside of the tire.

Shouldn't hurt. Weight doesn't matter that much, I have strong legs.

Hope you fix your bike soon!

And then again, maybe it's just your rim was originally a little defective or developed a micro crack that now gave up. Lots of people pump to those pressures...

No one seems to mention exploding like you did though...

Go figure..