I'm not normally a supporter of this kind of stuff, but check your local area for strees reduction activities (Yoga, stress relief classes, etc).
Sounds like one more burden in an already busy schedule, but from your description, you really don't have anything you can drop from your schedule right now.
My wife used to go to Yoga classes once a week, and to be perfectly honest, I wish she still did. It burned a lot of stress from her, meaning she didn't take it out on me.
Also, see if someone will watch the young'un for you so you can go for a walk. Just stroll around for an hour or so and think. If you can (safety and whatnot), do it alone so your thoughts can wander where they will without someone to distract you. Again, not my favorite past time, but it does help.
And, speaking as a parent, GET SOME SLEEP! Sounds impossible with a new baby around, but make whatever deals you can to try and get one good night'* sleep a week (at least). That, too, will do wonders.
Best of luck to you!
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