i might be the asshole here

ok so this is a bit of a long story. i am finishing up my phd and trying to get all my research published. i have this really great professor who helped me with some stuff, but honestly they are kinda intense and always want me to work on projects that will benefit them more than me. like we are not even in the same department anymore but still collaborating a lot. it’s not bad for my cv or anything, just feels unfair sometimes. so last week i got an email from this prof asking me if i could help them out with some data analysis stuff they need done by friday. i looked at my schedule and honestly it would have been impossible to fit in without messing up my own research deadlines, so i sent back a very polite no thank you. now here is the thing, two days later i see this prof post on social media about how sad they are that nobody could help them out with their work. everyone was congratulating them on some new grant funding, but they were still stressing and needed to get all of these analyses done in like 24 hours or something. i have been ruminating on this for days. did i really let down my prof? it feels petty to think about because honestly they are such a big deal in the field and always helping others out, but i am just starting out trying to make my name too. should i reach out and offer help now instead of saying no? or is that still taking advantage? what do you guys think?