Have you ever felt that no one understands you?
I think this happens to the best of us. There will be moments in our lives that we will feel lonely. Isolated, even.
I actually experienced this not too long ago. For the longest time, I've been associating myself with people who will talk to me for a while and then when they are done with me, they will ignore me, even though I am always sitting with them. Now that I think about it, the same thing happened to me a few years back, too. I know it's painful when you hang out with a group of people, trusting they would have the same interests as you or understand you, and at the end, they end up betraying that trust. That might mean that you haven't found the right people to be friends with. Even now, I am searching for that right group of people.
^ By the right people, I mean, people who you could forge a bond with, that you could depend on them, and you would not have to voice your thoughts to, and they understand and most importantly, they care. These people would spend time to get to know you for who you are and not for what they think you are.
As to how I cope with it; I have a category for people [I know it's not the best way, but it works.], for people who I just met, and probably won't ever see again or only see once in a while, I will categorize them as acquaintances. Sure, you might have a good time chatting with them, but will they spend time trying to get to know you better? Second, for people who open up to me, telling me their life plans and sharing their secrets with me, then and only then will I categorize them as friends. They are giving you their trust and probably are fine to talk to you about anything. If they don't understand certain things, do educate them. And if they brush off the things you tell them, it's a sign they didn't care as much as they should and you should put them into the "acquaintances" category. As I mentioned before, real friends will spend time learning about you, and they will not treat you like a chat buddy.