So, your short answer is write a message and hope to be rescued?
Continuing with your line of reasoning, it doesn't work... No one comes... Now what?
The question is not, "Will I be rescued if the message is found?" The real question would be, "Will the message be found?" I think you are missing something important. I would not be back in time if time travel was not possible.
If I am still around a week later then either the message was not found or the information I provided was not accurate. The next thing to do is to verify the date. If, after I have done everything I know to do to verify the date, my information is accurate then my message was not found. I would then find another way to send a message.
Jeanette Isabelle