My hair's almost exactly like yours. It's turned chocolatey-brown colour (I'm full Asian and I don't dye my hair) and I blowdry and straighten my hair everyday. Try not washing your hair once in awhile or letting your hair air-dry. Use cold water when rinsing your hair and always use conditioner.

I'd also suggest using oil treatments on your hair or try smothering your hair with conditioner, wrap a towel around it and wait around for half-an-hour to an hour. Rinse and let it air dry and your hair will feel a lot better. Hope this helps!