Pagenav links are appearing like this:

Page 2 works fine:
browselinks.php?do=browselinks&catid=2&ltr=S&page=2

But once clicking page 2 - trying to go back to page 1 gives this link:
browselinks.php?do=browselinks&catid=2&ltr=S&page=2

Clicking page 3 gives this link:
browselinks.php?do=browselinks&catid=2&ltr=S&page=2&page=3

But works - but when trying to go back to page 2 it gives this link:
browselinks.php?do=browselinks&catid=2&ltr=S&page=3&page=2

Which technically works - but it's impossible to get back to page 1.

HELP!