Rotten luck! I had a similar experience about a month ago.
Looking for a safer way into work I decided on a 20k ride along a river then a 20k train ride in. The river path was under construction, there was a fiendish head wind and about 17k into the ride my tyre wall blew out. Scrambling around at lunch I go a new tire and tube (the blowout trashed the tube too). I was looking forwards to flying home after the head wind only to discover it had changed direction and was fighting me once again! Ack! My average speed along this route is around 35Km/h. I was lucky to maintain 20

Today was a different story though. Nary a car on the road (comparitivly) I made the normal 50-55min commute in 45