Mine is always like this just before and after periods. Like Antonia said, if it doesn't smell or itch, and it isn't completely different to what you normally get (and even then it still might be nothing) then it's probably fine.
Google it rather than checking for old threads. If you still have reasons for concern after that, then doctors it is. And yes, I think they might want to take a look if it's an unusual discharge, especially if you are sexually active.