How often are you wanting to go to the toilet? Does it burn?
If its a brighter yellow and or feel hot (if that makes sense) when you go it could be that you are not drinking enough.
If it burns it is usually an infection of some sort.
If it lasts more than 2 days get yourself to the Drs as some infections can make you really unwell and uncomfortable.
If you are prone to infections get some cranberry juice, either drink it straight or water it down, I have been known to mix it with lemonade.
Hope its just a case of not drinking enough