Feelings are never stable. Our feelings change every few seconds. We can't control what's going to happen next and which feelings will result from whatever happens. To have this goal of having a certain feeling is not a very achievable goal.
Instead I recommend this way of viewing feelings: the feeling is never the problem. The problem isn't that you're scared or uncomfortable or unhappy. That's not the problem. The problem is that your needs aren't met. It's good that you have those feelings, but you need to make sure to not stop at the feeling, but connect to what your need is that creates the feeling. Imagine a world where you can't feel the feeling hunger. You'd never know that or when the body needs food. You'd starve and not even know it.
It's good that you have those uncomfortable feelings. They tell you that your needs aren't met. The problem is that in our culture, you're not at all trained to connect your feelings with needs. Most of us don't know what we need. So what we're trying to do is to change our feelings. That can only work short term. Instead, look for your need and find a way to meet your need. That's what will make a difference."