This is very strange...... possibly a glitch. I've came across a glitch or two, but nothing like this. It may also have been the fact you are only allowed to store 45 friends, but when you connect, it should come up "Sorry! List full!" Very, very strange......
Yes, all of your friends should not have deleted themselves. That's very strange, very very strange... are you sure you didn't delete them? :furawatchi: