colour will fade as it grabs on light hair and lets go fairly quickly to, im not to up on colour stripping....normal just go a toning route....but i would have thought even if u strip the hair back ur'l need a natural shade colour on top.
how long is ur hair? if you came to me id probably suggest colouring using ur natural shade with a semi to blend in whilst the part that was previously coloured would grow or get cut out but def go get a consultation, even go to a training college as they need experiences like this.
like i say u may need to invest in a little more colour for the time being but go seek a free consultation from a salon face to face as they can physically see what options uv got
hth