How can I bring this lemon tree back to life?

Ok. That is a very young tree and 39° is too cold for a tree in a pot of that size. Put it out in full sun and bring in at night. Stick your finger in the soil and see if it is moist enough. Trees in pots are more suceptible to temperature change than if in ground. It will recover if you baby it. I am not that far from you, but in zone 9 and have grown a number of trees in pots, I have a lemon tree growing in a pot too.

Joy then I think he's just really, really shocked right now. He moved and got repotted! Spritz or wipe him down with Neem oil just to be certain he has no aphids or whatever. And, it will make him nice and shiny! This is what I ordered (far cheaper than Home Depot, etc.)

https://store.doyourownpestcontrol.com/bonide-s-neem-oil-concentrate-16-oz

Give him some Miracle Grow or citric fertilizer as directed. He probably needs humidity if your heat is on. I'd spritz him regularly, don't keep him by the heat register and near your brightest window. Carry him to the bathtub to water him if possible. Water him until the water is coming out the bottom holes and if he's really dry (looks like he is), let it continue for a few minutes and then really dig your hand in to make sure the soil got watered.

https://homeguides.sfgate.com/water-meyer-lemon-63849.html