I went through something similar, after a month of playing nothing but Skyrim, and logging over 150 hours, I got kinda bored with it. Plus being on PS3, the Lag was making the game unplayable. So bascially i quit playing for about 2 weeks, played other games that i wanted to try out. Then got the urge to play skyrim again, and started up, and while i'm not playing nonstop like i did when i first got it, I've logged over 80 hours in my second playthrough already, and have hardly done any of the guild quests, and still haven't even visited all the major cities yet. Which also has me wandering how i've been playing my new character for 80 hours and still don't seem to have accomplished much.
I'm on the same boat as you.
Madmole already did a good job explaining why. It's actually a fairly typical problem with Bethesda's games, in that there are so many little niggles and oddities that the game never really lets you in. Awkward dragon animations, incredible amounts of repeated dialogue, companions, more incredible amounts of repeated dialogue, combat that feel like slashing at smoke, companions, giants sending you into orbit, and companions are what did it for me. Oh, and the lack of variation in the quests.
I've started playing again, but interspersed between Morrowind and Oblivion now. I don't think Skyrim will be worth a third full playthrough, really. I've seen everything there is to show except for a couple of Guilds and a few Daedric quests.
It's a good game, but it's just way too shallow. As opposed to the previous titles, it doesn't actually feel like Bethesda's heart was in this one.
Skyrim feels soulless. And that is why I have not been able to connect with the game. The stuff is there, but the spark is gone.