That's a rough one. I know a lot of people often feel super tired after work- it can be draining, mentally and physically.
If after work is the ONLY time you have to dance, I would suggest taking a little time out between the two. Do some meditation, eat a good snack, just replenish yourself however you find is best. It might take some experimentation to figure out what works, but a little transition time can really make the difference.
Also, what I found (when I was working and running after my shifts) is that you will have to ask first, and then receive later. You sort of have to do it despite not having the energy, do your best, and find your edge. The energy will come after a week or so of doing this.
It's the same principle for a very sedentary person saying they have no energy to exercise: They don't, because they aren't asking for the energy, so their body isn't making it. We're made that way, and energy conservation is very smart if we lived in the wild! But, if you had to hunt or run very often, then your body would make it feel easier, because being slow and sluggish can mean the difference between having food, or going hungry for another day.
So, remember that you will, eventually, have that energy... you just need to keep asking for it, by doing the thing, whether it sucks or not.
Best of luck!