Upvote:4
Penalties that may apply include a fine on departure, and/or a ban for one or more years. Certainly you will find it difficult to get another Schengen visa any time soon.
Exact penalties and implementation vary by country. Spain has tended to be more relaxed about fining departing overstayers, while Germany and the Nordic countries have been more strict. Policies change, however.
The only way to find out what will happen is to leave. Be prepared to be questioned and possibly detained for a while.