Internet works fine, but it is like before.
Random downtimes, everytime I experience such a lagg, I ping my router via cmd, and then I ping the google servers.
Today I lagged and pinged my router, and had pings between 40-1400 with timeouts.
Then when that was stable again, I pinged the google.de servers. And the ping there was stable at 30.
There might be a problem with the surroundings of my router or my router in generall, I am not sure since my internet was fine not so long ago.