Sometimes it happens and dream recall can change for a reason or for no reason, there can be ups and downs, but it will definitely be back, think positive!
Try to lie still for a while as you wake up and remember the dream, also even when you have nothing to write, write something positive anyway, like "Couldn't remember any dreams, but sure they were fun and my recall will be back soon". You can also try using mantra while falling asleep, like "I wake up after each dream and remember it", memory practice can help too, try recalling whole day before going to sleep.
Also check out this thread: http://www.dreamviews.com/dream-sign...ompendium.html

*Moved to Dream Signs and Recall*