A festival is a wonderful kind of exhausting. Several days of dancing, sun, walking miles, eating oddly and sleeping badly all add up, and your body sends the bill on the Monday. The trick to recovering well is to plan for it rather than be surprised by it.
Protect the first day back
If you possibly can, leave a clear day between getting home and getting back to normal life. That buffer is gold. Use it to sleep, shower properly, do nothing in particular, and let yourself land. Going straight from a field to a full day at work is a recipe for feeling rotten all week.
Sleep is the big lever
You are almost certainly carrying a serious sleep debt. The most effective thing you can do is bank some proper rest, in a real bed, in a dark room. A long sleep, and an early night or two after, will do more for your recovery than anything else. Make your room as quiet and cool as you can. A pair of earplugs helps you settle if your street is noisy, and a fan helps on a warm night.
Rehydrate and eat properly
Festival food and patchy water intake leave most people dehydrated and short on decent nutrition. Drink water steadily over the next couple of days rather than all at once. Get some proper meals in, with vegetables and fruit your body has probably been missing. It is amazing how much better a few real meals and steady fluids make you feel.
Ease back gently
Do not throw yourself straight into intense exercise or a packed schedule. A gentle walk in daylight helps more than a hard workout while you are still depleted. Sort your washing and unpacking in small chunks so the post-festival mess does not loom over you. Little and often beats one overwhelming push.
Mind as well as body
A flat or wistful mood after a brilliant weekend is normal, the comedown from a real high. Be patient with it, stay rested and fed, and it lifts. If you feel genuinely unwell or low for longer than expected, speak to your GP. This is general recovery guidance, not medical advice. Rest well, and you will be ready for the next one.