Chemical damage can happen to anyone. Your hair history, the diameter of each hair, the strength of underlying pigment, and the steps your stylist takes to give you the hair you want all come in to play when you're getting your hair colored. The more experience your stylist has in his/her career and the more experience your stylist has with your hair, the less likely chemical damage will happen. It pays to stick with the same stylist and to trust them when he or she tells you "no".
If your hair is mushy when it's wet, takes forever to blow dry, tangles up while you're drying it, and looks frayed when it's finally dry, then it's chemically damaged. It won't hold color, it can't be lightened, and it has to be babied. You can gloss it with toning color glosses if you need to, but it's best to leave it alone until some of the symptoms improve.
The best tools that I've found to heal chemically damaged hair are Olaplex No.'s 1-5. Olaplex No. 1 & 2 are done in the salon, and Olaplex No. 3 (treatment), 4 (shampoo), and 5 (conditioner) are the take-home treatments. These will actually multiply the bonds in your hair and help rebuild it over a fairly short amount of time.
While you're rebuilding your damaged hair, try to avoid blow drying it as much as possible, be gentle when you comb it out, and avoid using heat styling tools. If this is too restrictive, you may just need to cut off the damage. If you want to fight for your hair, then you can order your take-home products below and schedule regular (every week, if possible) Olaplex treatments.