6. Qb3 would have been a nice alternative, start the queenside pressure up nice and early. My engine has you up almost an entire pawn if you play 7. cxd5 cxd5 8. Qb3 (or ...Nxd5 9. Nxd5 cxd5 10. Qb3) instead of castling. Really, the biggest critique I have here is that you look lost. Remember, when your opponent plays the slav defense their queenside is going to be weak, so Qb3 is a strong move if you get the opportunity to play it. If you insist on playing this line again in the future, however, I'd strongly suggest you play 12. Nxe4 Bxe4 13. Nd2. Now when the bishop retreats, push f4 and push your lead in development by launching an assault on your opponent!
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I considered Qb3 but didn't like the idea of Qb6 where black gains a tempo if I want to leave queens on so I eliminated the candidate. f4 would grip e5 nicely but leave e3 and the e4 square pretty weak.
Every move you make is going to create advantages, and also weaknesses. You've got to be able to decide which weaknesses you are able to tolerate. Qb3 is a fine move against the Slav, and why on earth would you want to leave the queens on the board against an expert? Get that power off the board and simplify! The expert will likely not play Qb6 for the opposite reason, so he can maintain the complexity later if he wanted.
Remember, you're playing white against an expert. He's not going to beat himself, so you've got to make the conscious choice to man up and take it to him!
Just an idea here, but how about 12.Nd2? The idea is to remove the target of the pawn pushes, contest e4, and to play f3 and e4 if possible. Black has played some loosening pawn pushes on the king side, his king is still in the center and his rooks are unconnected. With white's rook on the c file, black has problems castling queen side, he's already ruptured his king side, so his only option is to stay in the center a little longer. You are castled and slightly ahead in developement, so you need to take advantage of the two tempi (h6 and g5) and react quickly in the center. The only way I can see to do this is by Nd2, f3, and e4. Hope this helps.
Yeah I thought about Nd2 but didn't want to take Ne5 off the table. I noted the loose kingside pawns but couldn't find a good way to exploit it. I went for a Carlsbad since I'm familiar with the strategies associated with that pawn structure. Thing was, I played a sound bishop sac against a 1600 and won the other day (also just a club unrated game) but the pawn structure was different.
Basically my plan was to get darksquared bishops off the board (since he'd be weak there) while restraining the c5 pawn advance. I also had the chance to play Na4 at some point and should have even welcomed b6 as it weakens c6, but then found c5 afterward so I eliminated Na4 as a candidate.
11.Na4,b6? 12.Rc1,c5 13.dxc5,bxc5 14.Bb5! would have even been a winner though I was thinking of the potential for c5 not necessarily the immediate c5.
My big problem was being too afraid of threats that weren't real and repositioning my king. The engine now says Bxc6 is best and even a clear advantage after a half hour after I forgot I had it running.
I think my other big problem is being too indecisive (finding the potential behind Bb5 but not following up when it's good to) and chicken.
As for queen trades I'm typically proficient in major piece endgames and like keeping them on if I can help it. Speaking of major piece endgames I'll show one in the game showcase I played well 
Oh, don't worry, we can see your indecision just by reading your annotations. You literally try to play chess like a computer, it seems. Human beings aren't made to size up and respond to all threats. Pick the important ones and act accordingly. You'll either be correct and win, or be wrong and learn something. That same expert may well have beaten me, especially if it's OTB and not correspondence, but I would have had a plan and made him foil it, rather than have him just wait around while I chase my tail and implode.
Looks like I wasted too many tempi defending against ghosts: