If you bought the laptop new, and it is only 6 months old it should have at least another 6 months warranty on it. You should try talking to the shop you bought it from or failing that ring up Toshiba themselves.
It sounds like an actual fault with the DVD drive to me, although you could try getting one of those cleaning disk things, it's possible that it's just the lens is dirty- so it's having to spin up fast to try and read it.
Also, if you look for updates for your model of laptop on the Toshiba website, it's possible there is an update for your DVD drive which might fix it too. (I had to update a friend's DVD drive firmware the other day which had somewhat similar problems- and it fixed them),