2008 1.6 hdi lack of power ?

Hi, this is my first post. I have a 2008 1.6 hdi 166k.
Had it a couple of months and it's been ok and very nippy! Recently the power seems to have gone, there's no oomph in it anymore. Before I used to put accelerator down and it was very perky, now very little happens.
Any common probs that can cause this, feels like something blocking it from going!
Thanks