"We can't talk about a lack of good fortune in front of goal because we did not create a single opportunity against Newcastle," the French defender told The Daily Star.
"It was the same story against Leicester and I hope it does not continue. We don't seem capable of winning a match any more. It is hard to bear but it is down to us to react and be mentally strong to turn things around.
City boss Kevin Keegan has preferred Richard Dunne in favour of Sommeil in recent weeks and the former Bordeaux man has discussed the issue with his manager.
"I am not used to being on the bench, it is hard to put up with. I went to see the manager and he said he didn't have any problem with me - it was just the time of the season that required him to leave me out," Sommeil said.
"He has made new tactical choices and that explains my presence on the bench. I know I have nothing to be ashamed of and that I have started the season well."