This is coming from my personal experience and I have always felt the same, cried about the same and felt betrayed and angry of the same. However, the more I thought of it, the more I have come to realization that the problem is not with my friends, the problem was with me.
Look, we have all had friends for different purposes. Perhaps you have set your boundaries to the friendships you have had without having had to discuss with them first. It's called setting expectations. If you express no expectations, then how can you expect your friends to help? Either that or you have a bunch of crappy friends (like I did). The part of being an adult is realizing that you can't always maintain the bond of friendship in equal circumstances. Just because you were there for someone during a crisis does not mean that they have the wherewithal and the ability to help you back. Sometimes, you have to realize that those who helped you then, may not want to help you now. There's a quote, " People come and go in your life for a reason" Hence, it's time to get more new friends if you have run out of the ones who chose to help you.
