The following example code:
require(ggplot2)
stats <- data.frame(Day=0:5, Mean=c(3.2, 2.7, 0.8, 0.2, 0, 0), Q10=0.0, Q90=c(7.48, 4.0, 2.2, 1.2, 0, 0))
plot
The problem is with your scale_x_continuous() statement. You set the limits= starting from 0 but for the first bar "T" is outside this limit so it is removed (you the warning that for geom_path() one row is removed). If you set limits= to for example star from -0.3 then "T" appears.
+ scale_x_continuous("Day", expand=c(0.02,0), limits=c(-0.3,15),
breaks=0:15, labels=c("DOS", 1:15))
