my friend who I am with almost 24x7 saw my medical school notes i have been working on for the past 3 years and it's not just lecture notes, it's every piece of knowledge/mnemonics/test question i have found arranged topic-wise organised, and asked me to share it with them?

i gave it to them right away as soon as they asked but felt so wildly uncomfortable that i had to tell them i realised i am sharing more than i'm comfortable with, and im happy sharing notes on anything specific if they need but didn't want to send everything all at once? i also mentioned sometimes i draft personal texts as well, so they might be around somewhere in the notes that i may not be aware of.

they are close to me and i usually love helping people but this felt like too big of an ask and i feel so uncomfortable sharing them all with her once. and it's not like they are struggling with their coursework that i'd go out of my way to help and give them a boost.

they have previously shared their notes/mindmaps with me to try and be helpful and tbh, i don't find them very helpful but i accept them as it's sweet of them to want to share in the first place. but it got me thinking that just because they felt okay sharing their notes, doesn't mean i should? i feel really awful giving away all my years worth of work like that but i also feel awful saying no as i feel like i am gatekeeping/being competitive w them? when that isn't the case. i just feel it's unfair for them to even ask for it in the first place since they can appreciate how much work i have put into it?

i don't wanna come off as selfish but at the same time don't want to be in an uncomfortable position where i may start resenting them ifykwim? cuz deep down i know i am not fully okay with having full access to everything i have ever noted down.

am i valid in feeling this way? am i being selfish? am i bad friend? how would you feel in their position :')