I am finding that I am light headed lately after doing Liver Flush number 4. I am also on the herbs from sensible health. I don't have the yellow discolouration in my poop, but I also take chlorela and spirulina which makes it a bit green.
The yellow part in your stool sounds like stale bile is moving out, which is a good thing. The reason I say that is because I do the Andreas Moritz liver/gallbladder flush, and when I did my first one I had to prep by drinking one litre of apple juice a day for the first 6 days. I found my poop was yellow leading up to the liver flush, which Andreas said would be due to stale bile. I used the same protocol for my second liver flush... however I did not have the yellow eliminations leading to the flush. I also was not on chlorela and spirulina at the time leading to my second flush.
I would guess that you removed a blockage in the liver that can now detox old bile :)