Waking up too early is fun!
Finding out part of your train schedule got borked (Schienenersatzverkehr) is the worst.
Today will be both fun and potentially an absolute horror show... Bah. F U Deutsche Bahn. :(
TLDR about "Schienenersatzverkehr": There is now a bus instead of a train and in 99.5% of all cases, you either don't find the bus at all in the first place because it's location is specified nowhere, or the driver is so confused that they run ultra late, or even that bus doesn't come for one or the other reason. SEV is always bad, a problem, a nuisance, and a goddamn pain in the ass. x.x