I haven't fed DS from righty for about 2 weeks. He has been using lefty exclusively.

I just expressed a little from righty and it was a pastel yellow colour, syrupy, and tastes quite salty.
Lefty is clearish white, thin and sweet.

Is this just because he hasnt had that side for a while or should I be on the look out for mastitis?
I feel ok, a bit tired but I'm still trying to kick the fatigue from having shingles, so its probably that.