I agree with joe'smom - more pictures would help. I see nothing wrong with the pink, but it's your quilt. Would it work to keep the blocks you've made, but make the new ones with yellow, and mix them up in the quilt? Then if you still hate the pink, I would start ripping it out. Other corrections may seem like they would take less time, but it will probably go pretty quickly, and really is the best solution - if you still hate the pink. (You've probably already spent more time thinking about other solutions than it would have taken to un-sew and replace the pink. I find I do that all the time.)