u/Disastrous-Fix-2169

Hey, this is my first year ever with planting hydrangeas. I planted this one on Sunday and watered it Sunday & Monday and skipped Tuesday because I knew it was going to rain today(which it is raining right now) and I noticed some yellowing. Is this transplant shock or is it happening because I skipped watering on Tuesday?? Its planted in clay soil zone 8A. I mixed the soil with some soil conditioner & garden soil for better drainage.