Not impossible but you have to play some games.
Method 1
You could slow the processor to 1/10 the speed and the 2 seconds become 20. Then you could turn the LED on at the start of the program, then off, then wait for the WDT to expire.
Method 2
Use a counter variable but do not initialize it in the normal way.
If the counter is not between 0 and 10 you set it to 0.
If it is < 10 you add 1 to it.
if it is equal to 10 you blink the led and set it to 0.
Note that this could be off by a count or two but you can figure that out easy enough.