My hair changed characteristics but I don't know how?

I'm a 16 year old male. My hair use to be very sleek, straight, and non frizzy. Now its still straight, but it is kind of... fluffy I guess your could say, and a little bit frizzy and wispy. I thought it might have been the way I was using my shampoo and conditioner. So I stopped using the conditioner, but that didn't help. Then I tried leaving some conditioner in, and that didn't work. Finally I used the conditioner, but rinsed most of it out to where there was barely any at all... What could be making it do this? Is there away to make it go back to the way it use to be? Or could this be one of the affects of puberty? It also seems to be a little lighter in color now.