Yellow spots on pillows?!

I know most people describe these as sweat or drool stains. But here's the thing. I stripped the bed to do my normal washing. I wash all my sheets in hot water, bleach and detergent. When I started to put the clean stuff back on the pillow, it noticed it had small yellow spots all over it. I can't figure this out, as I use a pillow protector and then the pillow case. I don't recall seeing these spots on the protector or case. Is this mildew? I had these same spots on a decorative pillow I have and figured that was mildew or some kind. I smelled the pillow and there is no odor. I do not drool too much in my sleep. I have candida, so this is a concern to me. Thoughts? Thanks.