1.) This is one of those moments in which the Ring does seem to have a
fully independent will that it uses on its possessor. (On other occasions
it merely seems to reflect back to its bearer what he already thinks.)
Tolkien's presentation of the Ring is purposefully inconsistent in this
regard.
2.) I think that Gollum fears that the Ring will give Frodo away -- and
thus fall into the hands of the Nazgűl. Gollum's biggest worry is that
he won't get the Ring for himself. His plan depends on getting
Frodo into Cirith Ungol; and Frodo's behaviour is putting all that at
risk.
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All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.
From the ashes a fire shall be woken,
A light from the shadows shall spring;
Renewed shall be blade that was broken,
The crownless again shall be king.
