O Shea, who could have been sent off in the first half, was also hopeful that Ireland can recover in time for their next game against Faroe Islands on Tuesday.
"Germany are a good team and they've made us look very ordinary tonight," O'Shea said. "They tore us apart really.
"We have to as quickly as possible dust ourselves down and forget about this as quick as we can.
"We have to get on with it, it's a terrible defeat and one we hopefully won't take too long to recover from because of our game [on Tuesday]."
Ireland are currently third in Group C with three points from two games.