Man I may be in trouble!!!

I just looked at my rear tire and the belts are showing through. I am at work and have a 50 mile ride home. I have 18500 miles on the bike / 9200 on the first tire / 9300 on this second tire. I guess the 100 miles was too much. I think the belts were almost ready to show through on the first tire. I have a tire from a trike take off at home ready to go.
Steve