Hmmmm.  I've had my hair toned recently, but it didn't seem to do anything.  Maybe my stylist just didn't leave it on long enough or something.  I really hope the pigment isn't returning to my hair, because that means more bleaching & more breakage :(

I think what is happening isnt that the bleach is darkening your hair...but you said you have been going lighter for a while,right? Well,hair does get darker as we get older,and tends to be darker in the winter months when it is not exposed to sun. So it is possible,that your natural hair growing in is darker,and not being bleached enough to make it as light as you want it now. maybe suggesting to the stylist to leave it on a few extra minutes to lighten it to the point where you used to have it.

Thanks for the response.  I went to the salon a couple days ago & my stylist confirmed that it is physically impossible for hair to darken naturally after it has been bleached - I mean the part of the hair that was bleached, not the regrowth.  I think my toner has just completely faded away & what I've been left with is my yellowy base.  I ordered a conditioning toner & I'll use it soon and post the results.  Again, thanks for the responses.  Always helpful.