It sounds like several things to me.
You're body may be holding some left over energy from the spell - energy that wasn't channeled or needed for the results of the spell. Sometimes that can cause things like tingling in your body, lightheadedness or being hyper, racing thoughts or zoning out. It can also cause headaches, shakiness, and other things along those lines. Its a good idea to ether go outside and place your hands on the ground and allow or push the energy into the earth or you can keep a large rock by your workspace and put the energy into that when you're done and let it sit outside on the ground for a while to discharge the energy.
It could also be that your mindset and body is still in a magickal state, even though the work is finished. If thats the case, its a good thing in my view. Use that time to do magick related stuff, like spell writing, research, incense making, etc.