According to ESPN's Week 4 Power Rankings The Lions are ranked 4th, the Bills are ranked 6th and the Chargers are ranked 9th. All 3 of our losses have come against top 10 teams. The Lions were ranked 18th in preseason and the Bills were ranked 31st! You can't tell how hard the schedule is going to be based on the previous season.
The Good news is our next two games are against the Vikings (28th) and the Colts (30th) who started out the season ranked 8th. If the Chiefs are going to turn their season around, NOW is the time to do it.
I don't put a lot of faith in power rankings, especially this early in the season, but the point is that you can't always tell how good teams are going to be until they play some games. Maybe by the time we get to the "tough" part of the schedule some of those teams will have fallen a few notches (like the Eagles, Falcons and Bears have done already.)