When I send someone a text message and they don't reply immediately, I will imagine many possibilities in my mind and I will have a very ominous premonition. ...

The main reason is that you are too delicate and easy to have many ideas. In fact, others don't have as many ideas as you think, maybe they just don't see anything at the moment.

Don't think too much about yourself. Thinking too much will aggravate the suspicion, and the more you think about it, the more uneasy you become. Don't think too much about yourself, reply to a short message or what to do after sending it, and don't pay special attention to what others will do, so it's okay.

Otherwise, if it really doesn't work, just call and let me know, which can save the waiting time and may be better.