Depending on where you live, it could be the weather changes that are affecting your hair. I live outside of Philly and our dewpoints have really dropped.
My hair is fine/low porosity, too. Baking soda just makes it hard and dry--even if I use 1/4 t in a recipe that calls for a T! I can't use straight oil/butter, but can use them in well formulated products. The Shea M Coconut & Hibiscus line is way too heavy (I use really rich products, if you understand the difference), it just sits on my hair and needs to be washed out.
Some of the products in my signature might work for you.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08
HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic; Botanical Spirits Jellies, CJ Repair Me