I have highlighted my hair so many times and so it's pretty much bleached out now and I want to color it a dark blonde or a light brown and start hightlighting it again.Does anyone know how I should go about doing this without my hair falling out or turning a strange color? And how lond after coloring it should I wait to put highlights back in?

I think this is really a hairstylist project. When dying over blondes, some green can come out, and it's scary, trust me.

Go to a hair salon.
Your hair might be damaged and dying it more will make it snap off! And that sucks.
Sometimes it can go a strange colour.
Try using a treatment to repair your hair before continuing.
You might not get a perfect shade the first time you attepmt it!
Good luck (:

I had a similar problem! I tried to dye over my bleach blonde hair with a light brown/dark blonde. It turned out this silverish colour! Yu have to put a red dye in your hair first. Leave it for a day or so then dye it light blonde. After that I say leave it for a few weeks... then get highlights. Hope it helped :)