Back on track
Ok, that happens when you try to do all things by yourself. Yesterday I was doing an upgrade on the server via apt-get which basically killed my ssh access to the server. I kind of know now what happened: the upgrade was updating two lines within /etc/init.d/ssh script and the ssh daemon was simply not working anymore after that (though I still don't know what exactly these two lines were for). Nginx was also running into some problems to this time, so the whole blog was down. How this nginx problem was related to this update is still unknown to me though.
Since my access was limited to the server I got no choice than to re-initialize everything. I also needed to reinstall all the software on the server and set up the blog again. Sadly I forget to copy my db dump before (that will not happen again :P). Good that this server has only my blog here and there was not much data in it yet.
Also I am way faster now to set up a server running Django projects.