Bristol City have now lost both their fixtures in the opening two weeks of the season, though they were undone by a hugely dubious penalty decision and a deflected goal at Hull City last weekend.
Pearson said his side are leaving themselves with too much to do.
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“We're two games in and we've conceded five goals," Pearson said.
"I can argue last week that we were unlucky but I can't argue with that this week.
"The first is an individual mistake, the second we've got a throw-in and they score a goal from our throw-in, some really poor defensive work and the third one... it's just too easy for them.
"Even when they scored the third we've still had chances and opportunities to get back in so it's a frustration but two games in and concede five goals. We're giving ourselves far too much to do in games.
"Credit to them they put us under pressure. Their front two were quite lively but we still made basic errors which we've been punished for and that is a big frustration.
"We've dominated possession today and we're not really a possession-based side. But we've had around 60 per cent possession but not been able to do enough with it.
"I still think we created enough opportunities to get something out of the game but unfortunately we've scored two goals at home and still haven't got anything and the big thing for us is our defensive frailty and that's the problem.
It's not a day where I make excuses or look for positives that aren't there. If we concede goals like we've done today, we're going to have a tough season.
"I don't think I need to pick the team up right now quite frankly. They have to feel the pain of losing first and I'll pick them up later, but not now. It's got to hurt them."