It sounds like build up. It seems you've only been using the products that work for you for a couple of months at most - I assume you found them after the sulfate mistake (I've done that, too, lol). Try clarifying - a simple BS wash should work for that. Also, are you living in a new location since school started? The water could be different. Hard water can cause problems.
remember, with all advice or suggestions for your hair, YMMV!!
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
LI: KCKT or CJSL
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)
Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.