I agree with Anna, could very well be a growth spurt.
With regards to the DF. It can take up to a week before you notice any difference. However with the DF it can go either way. With some lo's it helps them sleep better, and with other lo's it can actually disrupt their sleep pattern and cause more night wakings. But I would definitely suggest giving it at least a week to see how things go.
Keep us posted on how you get on.