Struggling With Increased Responsibility

Hi,

Around 1 year in, team changes have made it so I’m “in charge” of around 18 names now. High frequency publishing team as well so I have been struggling in terms of missing small (but key) mistakes more as of late. I think I understand the process very well but I struggle with the little things, especially when it is a company that I am picking up on. Not looking for sympathy here, but has anyone been in a similar situation/know someone who has been before? Im clocking like 15 hour days and still feel like im falling behind and I get the sense that my manager isn’t pleased with me at all either, so any help would be really appreciated.