Thinning hair!

I bought this whole line and have been using it for about 6 washes, and I have noticed my hair is very thin and is coming out in clumps in the wash. More than usual I mean. My hair used to be thick and curly, and I’ve noticed it has lost its curl (even after cutting 6inches off) and I can now feel strait to my scalp on the back of my head. I have also developed really bad dandruff that I’ve never had before. I can’t say for sure it is this product line, but it’s the only thing I can think of that has changed.
I would suggest trying a sample size if you can find one before buying.

This is a moderate to low priced professional conditioner. It's very thick and it leaves my hair feeling heavy and greasy. I still have half the bottle and I wouldn't use it or buy it again.