Those levels are definitely high.  My doctor like to keep mine between 2 & 2.5.  My levels got up to 7.5 where yours are, but I didn't have a lot of symptoms, which can be extreme fatigue, weight gain.  They will put you on levrothyroxine (synthroid) to get your levels down.  You should be ok within 6 weeks.  I would definitely stay on top of this though.  It can cause problems with having children, and just all around make you feel like shit.  You're doctor may also want to have your antibody levels checked.  Mine were really high which means I actually have a condition called Hashimoto's disease.  It usually doesn't onset until you are in your 40's or after childbirth, but I guess I am one of the lucky ones who gets it anyway.

Good luck.  No need to be scared.