We can’t tell you why you don’t comprehend stuff because we aren’t you. We can help you figure it out but you need to do the heavy lifting. Like I said, find something with subtitles, look through it, and see what you don’t understand without looking it up. I or many other people would be very willing to check your comprehension on here if you posted it with your translation.
If you watch through once without subs, especially, then that will give you
- An idea of how many words you knew when you read them but didn’t notice when you heard them
- How much of the grammar and words used you know from previous study
- If there is anything you think you knew that you didn’t
- What the missing pieces of knowledge are that were holding you back from full comprehension