Out of gas

When I was commuting in this morning, my bike was suddenly stopped. The reason was
out of gas. I had to walk to gas and bring heavy bike. Fortunately, there was a gas stop near by the point where the bike stopped. But, it was a hard job.
The accident was occurred, because I failed the calculate the distance of bike's running. And, the tank of my bike is too small to use for commute. The volume is only 5.5 litter. So I have to feed every 3 days.