You may feel dizzy so by having a light meal after each attunement is a good idea in order to further assist in keeping you from feeling light-headed. Please don’t be alarmed if you have these or other flu like symptoms after the attunement; this happens sometimes. Some teachers have affectionately termed the various post-attunement symptoms "the Reiki Achies". I call it clearing of toxins and some have called it crisis healing.
Take lots of rest of during this time by eating well, drinking plenty of water, and getting enough sleep. Also, and equally importantly, give yourself a Reiki treatment and Reiki balancing each day. Also remember to thank your guides and angels.