My hair is dark brown and is long,,,, it is past the end of my back, My hair grows like a weed I might add. But question is I take very good care of my hair always have, but for some reason lately my hair after the following day of washing seems to feel like heavy and look stringy... It has never done this before. What do you all think it is? Im always conditioning it so I can comb in out and I do not wash my hair until the end of the week. My hair is always up and never down unless Im at home and its a cold day.

I dont have a clue what Im doing wrong? Im thinking mabe I have build up on my hair? It just dosnt look the same like when I was younger. MInd you im only 29 but when I was 20 my hair used to look flowing? any ideas to what Im doing wrong?? 

also is there any other way I can make my hair thicker?

thank you I will do the viniger tomorrow and see how it feels afterwards and ill let you all know how the out come is.