Interesting read this thread. Been going to Ibiza for years and definitely get the blues every time. Never cried on the island itself but have broken down a few times after getting back. Not about Ibiza itself but about life in general, its futility, the fact that we're all going to die one day... obviously it's just the brain crying out after having its chemistry relentlessly assaulted for a week, but it feels more profound than that. The flashbacks of glorious moments in the clubs, strobe lights on beaming faces, high fives with strangers, all of that - in those moments you would give anything to bring them back to life.
A few things have helped (sort of). First, going at the end of summer rather than earlier - if you (I) come back and autumn is already setting in then I find that easier to take than coming back with two months of summer to go and the knowledge that thousands of people are flying out there every day for their holiday on the island while I'm sat at home. Second, for each of my last three visits I've been convinced that it would be my last one (or at least my last clubbing holiday there). This feeling of resignation made it harder to come home, but once I was home I started thinking about my new life post-Ibiza. Somehow this feeling of "drawing a line" helped. (Obviously, I have been back twice and will again this year, so things don't always work out the way you planned...). Thirdly, football - throw yourself into the football season (watching and playing) and this can take your mind off things. If you're not a fan this won't help I guess. Fourthly, taking up skiing/snowboarding gave me a winter holiday that is very nearly as exciting and physically exhausting as summer holidays in Ibiza. Truth to tell I look forward to both equally, except in my circles a snow holiday is more "respectable" than a week of chemicals and dance music. Other than that, all I can suggest is feeling proud and privileged that you get to experience something that the majority of the human race never does, and never even has any idea about. The comedown is only a measure of how high you've climbed.