She seemed annoyed when I asked about plans for next week

When she gets annoyed at a normal question about future plans, she's probably not annoyed at you. The question forced her to pick a side. Either she commits to something with you and risks disappointment, or she admits she doesn't know yet and feels like she's letting you down. Annoyance is how she avoids deciding. She might also be dealing with something else entirely and your question just hit at the wrong time. Don't read annoyance as losing interest. It's usually just discomfort with not knowing what comes next.

Your reply needs to do two things. First, back off the plans question entirely. Don't double down, don't rephrase it, don't ask when she'll know. Just drop it. Second, show that you registered her annoyance without treating it like a crisis. A light acknowledgment works here: something that says you're not blind to her mood but also not going to spiral about it. This gives her permission to relax and actually think about whether she wants to see you, instead of feeling cornered.

Don't reply right away to the annoyed message. Let it sit for a few hours or overnight if you can. A quick response to annoyance often looks like you're trying to fix it, which feels heavy. After a day or so, send something about something else. A meme, a thought about something she mentioned before, a question about her world. You're resetting the conversation. If she doesn't reply within a few days after that, let it go for a week. Then try once more, but keep it short and casual. If it's still one-word or cold, she's probably not that interested. Don't keep reaching.