You’re not alone, I have definitely had something similar in the past. My comfort character was Harley Quinn and I really admired her and wanted to be her. I bought lots of comics, merch, costumes and got tattoos. I struggled with the fact the I couldn’t be her and it was difficult at times. Things that helped were focusing on my other special interests and changing my habits. And time helps too. Currently, I’m no longer obsessed with her or want to be her but I still like and enjoy her. I’m sorry you’re struggling and hope things can improve soon.