I've learned this the hard way too. It sucks but at the same time it shows me who my true friends really are. Who to stick with and who to walk away from. You're always going to find people who put themselves and their problems before others (as in it's ok for them to talk and talk about their problems but when it comes to really listening to you, it doesn't happen and you could tell them something and within a week say it again and they didn't even know you had said it in the 1st place - if that makes sense - probably why I don't talk so much to some - lol) but then you'll also find people who sincerely, truly care.