Something that was formative in my understanding of language was visiting Glasgow years past, and realizing that just an "accent" could easily knock me back to understanding only 20-30% of words. Still, based on context it was possible to get around and after a week I was up to 70-80% comprehension with locals.
In North England and Scotland, we pronounce words using short vowel sounds (bath, castle) whereas in the South, they use long vowel sounds (b-are-th, c-are-stle).
Not being able to easily pick out the vowel sounds makes it much harder for a non-native speaker to understand.
The so called "BBC English" that you probably learnt is based on a Southern England 'home counties' pronunciation.
You've got this. Try to remember to record yourself speaking periodically with others so that you can see how much you are improving.
> visiting Glasgow years past
I remember being in Gatwick airport and hearing my first heavily-accented English. Maybe it was a Scottish brogue. I could not really understand anything.