Feelings are largely indescribable. If you disagree, then try to describe them. It will probably end up sounding like crappy high school poetry (and for good reason). Feelings are not the only indescribable things. Experiences can be similarly impossible to put into words.
But just because something is indescribable does not mean it should be ignored in writing. Think about those feelings and experiences. If you ever found yourself telling somebody that "you had to be there", then you already know what to do as a writer: put them there.
Don't try to explain how feelings feel; explain what made you feel them. When you spend two thousand words explaining how a young boy was totally in love with a girl from afar, and then one day he gets invited to hang out with a group that she would be in, then when you describe his racing heart and tingling arms, we will understand plenty clear. When he finds out that she actually seems as cool as the idealized image he had of her, we can feel his elation. And when he finally gains the courage to ask her out, we can feel all of the rollercoaster of emotions from the eternity of time waiting for her answer and having literally no clue what it will be, finally hearing the response, and everything else that naturally will follow.
These are feelings that we have all probably experienced (we share life), or at least can mentally imagine with the right words. And that is an important point, too. Your words do matter. You do have to be good at describing things. You just have to realize what you should be describing. People have to have a very clear picture of the scene, the history leading up to it (which explains why the things going on are significant), and what exactly is happening. Once we know everything else involved, we will be able to come as close as possible to feeling that feeling that "you had to be there" to feel.
So, you shouldn't try to describe the indescribable - just try to describe every single other thing.