Vibe is kind of a hard thing to get on demand. I'd listen to some music that sits kinda near what you're going after, but be careful not to just imitate that music, just let it get you in that headspace.
If you're going for angst and spit, try to keep the new baby out of your thoughts for just awhile.

Babies turn us all into cooing softies. Especially me.
I used to watch movies that amped me up. "Falling Down" always used to make me want to beat somebody up, try that.
Get some exercise. Weightlifters and boxers work out to metal and hardcore rap, maybe try the opposite, get physical to get motivated.
Technically speaking:
Get a lot of sleep. Take a Tylenol PM if you have to, it makes a huge difference for me.
Have the lyrics printed out legibly and put on a stand.
If you sing better in front of a crowd, have a few folks in the control room, if you don't, turn the place into a ghost-town. Do what you need to do to get inside the song. If you get all squirmy about the engineer being there, turn around and face the wall.
My biggest problem is red-light syndrome. As soon as the engineer hits "record," I get uptight and start blowing stuff I've done a million times in front of large crowds. I can't offer much advice other than get a deep breath and do another take. Just do what ya do. So much can be done with non-destructive editing these days, you can fix a lot of tiny things at mixdown, or just do a punch-in. Old-schoolers see that as cheating, but Pandora's Box opened up 20 years ago... you have to make a technically good recording just to compete. Pitch-correct is your friend, as long as you don't come out sounding like Cher or Britney.
Finally, be you. You're a good guy, and you care about what you do. Let that guide you.----------->JMS