Data in Single Colum, want to turn it into matrix

I extracted data from a simulation into a text file but all the data comes in a single column (See attached text file). The column contains the header follow by time and amplitude data, then follow by another header which is in turn followed by another set of time an amplitude data. Also the length of each data set varies slightly from one set to another. I would like to know if there is a way to extract each header with its corresponding data set and put them in a matrix.

[Walter Roberson]

Is the header numeric or string? If it is numeric is there a special value to signal it is a header?