Oh yes, I can really relate to this. T used to get very frustrated at me. She would give me a menu of feelings of which I had to pick a few. She would say I can't help you if I don't know what you are feeling and that used to make me more distressed.
I find writing in a journal a great way of expressing myself because I am a better writer than speaker. In my head thoughts are easy to understand but expressing them is frustrating and people often don't understand me especially ex t. New t is better with this and has often said, maybe there are no words. She gives me lots of time to sit with the feelings. She has often brought out toys, art materials and clay I get so excited that I end up not using them.
I find the words will come when they are ready to leave you rather than being forced out.