So what can we do to encourage our own creativity when the spark seems to have gone? I go to a couple of writing conferences a year, carefully chosen, and find just immersing myself in writing with no distractions/other commitments can be really helpful for re-enthusing me about writing. I should add day courses work well here too. It really is a question of finding something to suit you.
Remind yourself of what made you put pen to paper at all. Think about your trigger points. Also if life events, illness etc are the cause of slowing yourself down, don't worry about it. Get over it as soon as you can.