I'm Croatian, do I need a transit visa for the transfer from pudong airport to hongqiao airport?

Can someone help? I'm flying Bangkok-Seoul via Shanghai. It's a complete mess: from Thailand I land at Pudong and to Korea I go from Hongqiao. How on Earth do they expect to stay in transfer and not have to worry about a visa. I need it, right? Thank you very much (I'm Croatian by the way)