why did you go so light?!
i did that once and it took years for my hair to recover.
you can dye over it, but i would give it a few days. as well, since you have stripped out all of the pigment, you will have to get them to fill in the missing pigment levels and then colour over it. it is time consuming and pricey....the other option would be to do a ton of lowlights, but that might go green if the hair isn't properly filled as well...could you maybe try a new cut or style to see if you like your hair better that way? if you do decide to go darker, make sure you get a really good deep conditioner and a shampoo for colour treated hair, because your hair will probably be really damaged and need some tlc. good luck!