history: I studied really hard for my annual exam but did not get my desired grade. it left me very disappointed in myself.  I usually study hard and get my grades but sometimes it doesnt work out.  Brain just wants to work against you?
current: Yep, basically my brain just abandoned me at the critical moment. I was so disappointed. 
next: I would get that a lot in school back in the day i feel it's pretty normal to have those moments.