My hair is really stressing me out?

OK, so I have hair like Zac Efron, almost identical. Except for the past few days it hasn't been straight. It's getting shaggier. I recently got it thinned out maybe a week ago. I do straighten it everday, i think maybe it is getting too dry. I've tried everything! The last time it looked really good was tuesday. I hate when it looks all shaggy and curly, and a few minutes ago i put some Biosilk in it. What can i do the fix this? Besides getting it cut, because i don't think thats the problem.