What are some signs that she has lost interest in texting me?

Look at the last week, not the last message. The useful signals are her reply length compared to how she usually writes, how often she asks you something back, whether she opens new topics or only answers yours, and how long the gaps are compared to her normal rhythm. If she used to send paragraphs and now sends single words, that is a real change. If she has always been terse, a terse message means nothing new.

Also check whether she is still doing the small things. Does she react to your messages, remember something you said, or reference an earlier conversation? A woman who has lost interest often stops doing those things first, while a woman who is just busy keeps the warmth in the messages she does send. Context matters too: a Monday after a heavy week is different from a Friday night when she has time and still goes quiet.

Once you have read the pattern, the next message should make it easy for her to respond without any effort or any pressure. Three kinds of message tend to do this. A light, specific comment about something she told you earlier gives her a thread without asking for anything. A simple question with a clear answer, like a choice between two things, is easy to reply to on a phone between tasks. A short, self-contained update about your day lets her respond with a reaction or a line and keeps the conversation alive without demanding a conversation.

All three should be short and should not carry emotional weight. Leave out any reference to her not texting back, any question about how she feels about you, and any apology for being a bother. If the message needs an explanation to make sense, it is too heavy for this moment.

Wait before you send anything. If she has gone quiet after a short exchange, one message is usually enough, and it should go out on a different part of the day from when you last texted, so it does not feel like a continuation of pressure. Sending a second follow-up within a few hours of no answer reads as anxious, and it hands her the feeling that she has to manage you.

If you have sent one message and she does not reply within a day or two, let it sit. Do not follow up with a question about whether she is okay or whether you did something wrong. If she comes back on her own, pick up the thread lightly and keep the energy close to where she left it. If she does not come back after a reasonable stretch, the conversation has likely run its course, and the right move is to stop texting and let whatever is left come from her side.