To Fix or Not to Fix?

I tried fixing one of my sheets of paper, didn't go exactly as I had planned! Instead of getting darker or staying the same colour as I had expected the paper became lighter and lighter as the fixer did its work and seemed to end up reverting back to it's original colour when it was first taken from the box. Then as it dried went a more pinky colour with purple tints at the edges.
I now have a battle in my head between fixing and allowing the paper to continue to change.