How can I deal with feelings I can't find words to express?

let them out, tell them someone, maybe they find words. Accept them, accept that your body can have feelings sometimes, that you cant understand. you are not alone with it.

I think you can deal with these feelings by expressing them through creative mediums such as painting, making music, drawing, doodling, etc. If you don't feel arty then you can still try to do those things, how your artwork look at the end isn't the main point it's the emotion and feelings that you put into it that really matter. And hey if all else fails you can always cry :)

find a way to express them through actions, writing a book, playing consoles or buying clothes online.

I keep a journal. I just start writing about whats bothering me, over and over until I feel better. Then I look back and I'm usually able to see a pattern in my emotions. More often then not, I'll state my problem in a few different ways, and from that, I'm able to find the words to what I'm feeling.

Sometimes, I find that writing a letter to someone about it helps. It can even be to myself. It doesn't have to be sent to someone but I think when you arrange your thoughts to talk about an emotion, you also understand it better. And sometimes learn to manage it better.

As hard as it might be, it's super important to identify your feelings before you try to deal with them! Then you're not trying to aid sadness with help for fear.

you can write it on a piece of paper and then rip it apart that way you can throw away all of those unwanted feelings

A lot of people often say they are sad, when really they are actually feeling lonely, or empty, or even just apathetic. For those that find it hard to describe their feelings, it may be best to note feelings that you are not having. For instance, I may know that I am mad, but a better way to narrow that down would be to ask questions like: "Why I am I feeling so angry? Am I jealous of the person that got the promotion instead of me? Am I bitter that my friends didn't invite me? Am I feeling down because I didn't do well on my test?" Asking a lot of "why-oriented" questions helps to narrow down our feelings to a point where it's easier to identify them.

You can express your feelings in a healthy way through art or music. You can create a visual representation of your feelings. For example, staging scenes and photographing them, drawing and painting, or creating sculptures. There are limitless ways to express yourself through art.

There is no perfect answer for that. One of the way is to meditate on it. Take yourself to a quiet place where no one will disturb you. It could be a park even with natural ambiance. Then think about it, introspect, do it on daily basis if need be. The problem will unfold itself and you will find that you don't need to solve it, finding the truth behind it brings peace.