Very similar situation here for Edexcel Eng Lit. I was a straight A* student and felt great about the papers. I ended up getting an A, one mark away from an A*. Having requested the papers back, I found out that I got 36/40 on one paper but 33/60 on another, a score that I have never even come close to getting before. Having read my responses back, it makes even less sense as the two papers are very similar in quality of answer. I've gone in for a remark and my odds are quite good thankfully but I genuinely think I'm owed at least 10 marks!! It's so frustrating and confusing but you're not alone!