I have found there are four kinds of writers: visual, verbal, action, and emotive. Each has strengths and weaknesses that can cause roadblocks. From your description, it seems you are a visual screenwriter. Most writer/directors are visual or action writers. Each style has strengths, weakness, writing characteristics and certain blocks. Writers dabble in all of the styles but there is usually a preferred style.
Visual screenwriters tend to see the scenes play out in their mind. They can see angle shots and envision rich sets. One drawback is they tend to write too much detail into their scripts. However, they often can see the whole plot arc for their story. When they get writer's block, it's usually due to dialogue and relationships of their characters. They know who is in the scene and can picture them interacting, but actually writing the dialogue to seem natural and move the story can sometimes bottleneck their writing.
Rather than set it aside, my suggestion is that you simply write a treatment where dialogue is not a concern. Finish doing your storyboard. I'm not suggesting you set aside your script, but rather focus your strength on visualizing the story.
You can opt to pull in a co-writer who is verbal. These writers are adept at provocative, natural, nuanced dialogue. Or if you go it alone, you might engage two actor friends to help you. Give them the previous, current, and subsequent scenes and character descriptions and let them improvise. And as it happens, record it then go back and pull out the pieces you liked for your script. It may inspire other thoughts. The beauty of working with a group of writers is that ideas are always tossed about by the combination of the four writing styles.
For the moment, just focus on putting the characters in the right places and describe the actions going on. You're looking through the window. Later after the storyboard and treatment, you can go back and eavesdrop and fill in the dialogue.
The story is still inside, so don't give up hope. Sometimes it is good to take a break. Good luck.