Instead of asking, "Why me," ask "Why not me?" If an exact replica of your problems were passed on to someone else on the Earth do you think they'd handle it better than you? Maybe you're the best candidate. Take it as a compliment rather than a burden. Instead of asking why you were chosen, figure out what to make of it now that you have been chosen. You can't change the cards you've been dealt, so bluff and make do with what you have. My favorite bible verse relates to this well:
"The Lord directs our steps, so why try and understand everything along the way?"
-Proverbs 20:24 (New Translation)