He said: "I think I'll have an ulcer by Christmas. There was a naivety out there. We're a very young side and we're going to have to learn quickly.
"There were spells in the game where we looked okay, but you're talking about 18, 19 and 20-year-old lads trying to perform at that kind of standard, plus the other ones, from the league below, got a little culture shock with the pace of this league. The tempo was difficult for us to handle."
He added: "We haven't even worked on playing against 10 men! We tried to make sure they knew what they were doing in the second half, but they got worse instead of better.
"My two centre-backs tried very hard to make sure that Stoke scored, but we'll all go away and have a chat and try to get ourselves sorted out for the next game. It was a roller-coaster of a day."