I just noticed that in my document every page consists of a large whitespace at the top. I have probably used some package that messed it up because I don't think it should be like this. How can I restore it to a normal spacing? Or what's normal?

I just noticed that in my document every page consists of a large whitespace at the top. I have probably used some package that messed it up because I don't think it should be like this. How can I restore it to a normal spacing? Or what's normal?

You can use the geometry package to adjust margins etc.
E.g I have
\usepackage[top=2.5cm, left=3.5cm, bottom=2.5cm, right=2.5cm, includehead]{geometry}
\geometry{headheight=28pt, headsep=18pt}
in my thesis.
But without a MWE it is hard to know if that would conflict with some other packages you may be using....