I would suggest a haircut every few months and regular trims until the damage is gone. You also need to do regular PTs (protein treatments) and since your hair is dry, you may need to DT more frequently.
Another thought is using other products. Most of us start with Deva and move on to other lines. My salon has the Deva products. The only one I let them use when I went in for my regular haircut/highlight was the NoPoo. They changed the ingredients a few years ago and I found it very drying. Now, no Deva for me.
Many of us rotate products because our hair satiates, if we don't. I wet, rinse out and style every day--seldom use any one product more then twice a week.
If your hair is drying out during the day, it's "porous." It could be a result of the "over processing," heat damage or you may just have porous hair. You may want to think of "sealing." If you search, there are a lot of threads. Some people use oils or butters, I just use richer products. It's putting a layer of something really rich that will take a while to be absorbed and help your hair retain the moisture. Some use a leave in first and then seal, others seal and then put in their other products.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08
HGs: Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; DM MiraCurls Curling Gelly; UFD Curly Magic; Shescentit LIs; Sevi conditioners; Botanical Spirits Puree, CJ Repair Me