I'm surprised you feel that way - I started reading after season one of the show, and I was pretty pumped at how much more material the first book had. The differences and extra content only get more pronounced and start piling up the further you go, though, so you should stay the course and keep reading them one by one.
I have a hard time believing anyone who has taken the time to register an account on an ASOIAF forum, spent some amount of time reading said forum, and has now posted in this thread on the forum would ever stop reading the series.
The whole chapter was so ominous, I could tell something bad was going to happen at The Twins. When Grey Wolf went off on the Freys and got put in a kennel, and Catelyn's POV kept making it clear that their only protection was the immaterial tradition of 'guest right', I had a strong suspicion that Robb was going to die.
Really, Starks? Trusting in an opportunistic old sneak like Walder Frey to keep to a tradition of being nice to guests? That's no way to run a kingdom.
"The King in the North arises. It seems I've killed some of your men, your grace."
Aw, come on... They aren't so bad and you know it.
Edmure is a softhearted dumb-dumb who really means well. The kind of guy that lets refugees stream into his castle when he's beset on all sides by enemies and might need all of his supplies. He's a sweetie, and not all that bright.
The Blashfish is an awesome dude who loves dudes. Gotta love a strong, non-stereotypical gay character, right? Brynden made a career and a legend for himself by being a wily and skilled soldier. He's a Westerosi special forces sort of fella, and he obviously has a lot of affection for his family. Gotta love the Blackfish.
Yes, she's definitely a pretty horrible character by the time she gets to us in the course of the narrative... She was put through some serious trauma, though. She was forced to abort her lover's baby and then forced to marry an old man she didn't like, being treated like soiled goods and a burden on Arryn's honor that he bore for the sake of Tully swords. Lysa hasn't had such an easy time of things. I've been pretty goddamn surly over a hell of a lot less.
Catelyn is... well... I'm not even going to go into this one here. But suffice to say that my opinion on Catelyn Tully-Stark is that she's unfairly maligned on these boards and in the fandom, like most (all) of the female leads.
Hoster Tully sounds like he was kind of a dick, this much I shall grant you.