AITAH for not letting my office mate have my last can of coke in the office fridge?

I genuinely feel like I've failed some social test here, but I'm not sure why 😭

Background info: I am living paycheck to paycheck, so I dont have the ability to go out and buy lunch every day at work. I also have to carry my daughters things to get nursery on the way to work, so I can rarely carry a full lunchbox for myself. What I do instead is, on payday, I will order about a week or twos worth of cheap lunch things to keep in the office. A few cans of drink, microwave noodles, multipack of crisps, etc. This is usually my only source of food and drink in my office during the month.

My daughter has been sick this week so I've been off work. I got a text from my office mate asking how she was, and then a follow up message asking to have my last can of coke in the fridge. I replied:

"Oh I'm so sorry, is it okay if I say no? 😭 I really don't mean to be a tight ass, I just don't keep coke at home anymore because (my daughter) is a fiend for it and the ones I keep at work are my only cans 😥"

She responded with just a thumbs up.

I made a joke about it to my sister sometime later, and she started berating me that it was a really shitty thing to do and I should have just given her the can. I was taken aback tbh, because I didn't think it was THAT serious of an event 😅

Now I'm worried that I've made a really bad social move and I'll have spoiled the office vibes.

So, AITAH?