Did you use pernament color? If you did, wait. You may actually end up liking it when you get used to it. If not, visit a stylist and have the color chemically removed. Unfortunatelly, it is more damage than dying your hair. If you like short hair, you may also wait a bit and than cut it.
Before you dye your hair with pernament color, try semis or naturals ( like henna) or just buy a wig. You will have an idea how you`re going to look like so you can see if you like it.