I think you should try these things:
1. Use a clarifying shampoo right away, and then every once in a while for now on. Follow each shampoo with a quality conditioner, based on your hair properties (find out about that at this site, using the search tool).
2. Rule out any problems your hair may have in reaction to protein or glycerin (can read up on that here, doing a search).
3. Read up on humidity and dew points, and make sure you're using products that fit the weather conditions in your area.
4. Get a hair trim or cut, and consider some layers (as M suggested).
5. Experiment: wash your hair less often. Twice per week may be stripping your hair of too much natural oil, resulting in dryness.
6. Step away from all that straightening you're still doing. Willing to bet that at least part of your complaints come as a result of straightening.