Do you apply your DT before or after you cleanse your hair? I find that my hair gets less weighed down when I cleanse after using a DT. Also, maybe the addition of extra oils to your conditioner is too much for your hair. You can try adding some honey to one of your regular conditioners and using that as a DT. The DT will also penetrate your hair better if you use heat. I recommend rinsing your hair, applying the DT, putting on a shower cap/saran wrap, and using a blow dryer to heat up the conditioner that's in your hair. After that, you can cleanse and condition your hair as you normally would.
Also, have you tried a protein treatment yet? I was afraid to use protein for a long time, but I recently started using IAgirl's PT and it makes my hair super soft and shiny and bouncy. Protein treatments can also help strengthen your hair and protect it from environmental damage.