I’ve accidentally turned reading my book for joy into reading as an assignment and now freeze when I think of reading it??

Hello, I’ve never posted on this subreddit before so please let me know if I should post this to a different one. I’m pretty sure I have adhd and from what I understand this is kind of a neurodivergent thing but I would like some opinions other than my family. My dad got me to read this book series that he’s still reading, and I love it and am one book behind him (he’s on book 5 out of 6 and I’m on book 4). My little brother went off to college almost two months ago and we got him to start the first book before he left. He took the second one with him and the plan was we would mail him the rest as we finish them (I had just started book three at the time). By the time he finished the second one I wasn’t done with the third and he bought his own copy so he didn’t have to wait for me to finish it and mail our copy. This is where my issue is and I feel silly talking about it, but part of what I love about being ahead of him in these is when he gets to certain parts he’ll call me and be all excited or shocked about what’s happened and I LOVE that feeling and connection. But I’ve kind of unintentionally put these books on a pedestal because of it and now I’m reading less for the joy of it but more in a sense that ‘I HAVE to finish these before he does’. And I know I don’t have to and logically it’s fine if he gets ahead or whatever but like I just can’t let him. It’s not about it being a race or something but in my mind I started them first so I have to finish them first, plain and simple. But because of this pedestal or whatever I should call it, I am now barely reading at all. So I make no progress and he keeps reading and getting closer to beating me and the fear(?) of that like freezes my brain and I can barely make myself pick up this book. It’s so overwhelming I cry almost every time I think about it too much. Is there anything I can do to not think this way or to just read the book like I used to???? He finished the first trilogy and said he thought he might not read the rest cause it had a good ending and I was so relieved but he just told me he started the book that I’m on and I’m once again paralyzed with this fear.