Folks with learning disabilities, especially folks in environments where there's a lot of shame associated with "different," get really good at masking symptoms & struggles.

It's way easier when you're younger (elementary/grammar school age; not sure what the term would be in your country) but as the work gets more difficult, your old coping skills and masking techniques start to fall apart.

You're not stupid; your brain just works differently.

Getting diagnosed really should help you figure out how to work with the way your brain works; no shame, just support.