I missed a connecting train because of a 5 mins delay with the previous train. I'm confused about an email I received from Deutsche Bahn too regarding this. My train from from Stuttgart HBF to Berlin HBF, however, there was a change at Hannover Hbf. 

I received this email Sunday, Oct. 23, 11:23 PM:

> ## Your connection in Hannover HBf will not be reached
>
> **Change is not possible**
>
> Good evening Bawa Singh,
>
> on your today's journey from Stuttgart Hbf to Berlin Hbf the connection in Hannover Hbf will probably not be reached. Please use the button "Find an alternative connection" to get your next possible connections. You can end the travel assistance for this journey by following the link below.
>
> Sincerely yours
>
> Deutsche Bahn

The next possible connection was after really long time, so instead of that, I booked a bus and traveled to my destination.

What does this email mean exactly?
Does it mean that it is my responsibility to find the alternative next connection to reach my destination, and Deutsche Bahn really does not care and is also not responsible for any inconvenience? Should I ask them for a refund? Or at least reimbursement for the bus journey? Am I eligible for that?