The Magpies – who were in mid-October as high as fourth in the league – now sit 18th in the top flight having lost eight of their last nine games, and are only three points above bottom placed Swansea.
“We have to keep calm. We have many games coming up in December and January,” he said speaking with the Sunderland Echo.
“I am very happy that we have a full squad. We will keep working hard like before.
“We have improved and I believe we will keep improving. I am sure we will get out of this situation.”