You would like to take a look to the hooch in your starter.
If the hooch layer is in top of the starter, it probably is ok. You could either discard the hooch or mixing in again. If disposed, be care with the flour/water percentage.
If the hooch is in the middle or in the bottom of your starter, it will be good to wash the starter as previously indicated.
Do not be worried about any of this processes, the preferment is, normally, strong enough to maintain himself alive.
I have three of them, two news ones, Camaldoli and Ischia and an older one (a three years Carlīs preferment). I had needed to wash the Italian preferment, as somebody indicates that could be happen with the starters coming from Sourdo.com and today there are happily growing. The Carlīs, well, the Carlīs had been sleeping in the refrigerator by weeks and always returned to life when required.