Food is grounding. Don't forget to eat, especially heartier, substantial foods. While it may be difficult to sleep during a spiritual power surge, do everything you can to get enough rest. Too long without sleep in and of itself can make us crazy. Don't be deluded into thinking that in your heightened energy state sleep and food are not important.
Creativity offers a good outlet for spiritual energy.
Paint something, make music, dance, write a poem or journal about your experience. Sea salt baths, swimming, even long showers are often recommended for cleansing and grounding. These are a few ideas for grounding and there are many others. The most grounding thing we can do, however, is to simply trust that our experience is a normal one. Our most powerful grounding tool is the choice we make in how to interpret what happened to us.