I am naturally medium blonde and now have quite a bit of gray. I purchased L'Oreal color #8 Medium Blonde. I have colored my hair many, many times, but not in the past year or so. Generally I would highlight my hair light blonde/medium blonde which looked wonderful. My intent was to color the gray and even out the color, however, my hair is now a cheap looking light reddish blonde. Is there a toner I can use to get rid of the red? I generally use L'Oreal because it is gentle and I have been diagnosed with male pattern baldness (which is debatable since my hair comes out by the root, doesn't break off, and eventually grows back.) This happens every two or three years but has never been successfully diagnosed as alopecia or MPB. Any suggestions? :(

It might be due to the amount of white you have now. For an example if you have 50% of white hair and you want to colour it, you need to mix 50 50. 50% of the target colour and 50 of your natural base which could be brown for an instance. And then mix it with the correct amount of peroxide.
I think another reason could be the colour might have built up.
You could try bleaching it out?

When you buy toner again get it with a neutral base. Apparently your hair is reacting to a yellow base.