I bleached my hair and it turned orangish gold(copper like) and I want to dye it back brown. What do I do?

This is not something you should attempt to do at home, you'll not only end up ruining your hair, you won't get the color you want.

You need a professional hair dresser, and even they may be limited in what they can do to fix this.

Good luck.

Any professional stylist with experience in color correction can easily correct this for you. A common solution is to use a demi-permanent color with an ash base, which counteracts unwanted red/orange/gold tones. Be aware there are different types of "ash", depending on the color level. For example, a green ash corrects red. A blue ash corrects orange. A "pearl" or violet base corrects gold/yellow. It is best to see a pro, but if you insist on trying it yourself keep these points in mind.