Troubled thyme
 

I had a lovely thyme in a 10" plastic pot with attached saucer. Leafy,
green, full of life. All of a sudden -- that is, within 2-3 weeks --
it's turned into a haystack. the stems have shed all their leaves
except at the last 2-3 inches, where they still look good. The stems
look dry and brittle. I thought this might be because we have had so
much rain lately, and perhaps the soil had become (and remained)
waterlogged. I've been tipping out the extra water regularly now, but
the plant doesn't look any better.

Does anyone know what this defoliation might be due to?