You had an anxiety attack because a friend was having one? That means you must have a lot of empathy. The brain can take on certain aspects of others that you are close to. Its like a mimicking thing, subconsciously. This is actually pretty common. Just realize that you are in control and you don't have to adopt anyone else's fears or actions. You should also realize that when people are going through some difficult times, they might not want to talk about it because they are dealing with it themselves. People can take care of themselves. Everyone is self sufficient even if it might not always seem so. Give them more credit, and have faith that they can take care of their own problems that have nothing to do with you. Focus on your own life, your own dreams, your own goals, your own emotions. This doesn't make you selfish or a bad friend. You cannot be a help to them if you're breaking down too - that's why its important to be healthy and strong within yourself so that they can look up to you for advice and for strength. They also might not be telling you certain things because they've realized it might pull you down into negativity with them, so they're sparing you. This is why you must show others that you are happy, healthy, free, and open to offer them advice or help because they can see in you that it is possible. Otherwise you're just down in the dumps with them and that doesn't help anyone - especially you. Good luck!