She's got a busy week, she's stressed, she offered next week. Sounds good to me, she didn't turn you down and she put a couple of kisses at the end of the text.
It's very possible she simply is stressed and busy this week. Don't put any pressure on her whatsoever. Here's my suggestion of a reply:
"Sure, if you're having a stressful week we'll do it another time. Is there something else you'd like to do this week instead, maybe a relaxing movie indoors with me cooking? I could do Saturday."
With all the rules and games around here, sometimes it makes guys overthink things a little too much. Just be straightforward and cool.