My Sim has disappeared!

[Majick]

LOL is okay, I did it too at first ^__^  Took me forever to realize it too.

Also, because a Sim is pregnant for 3 days, if they are less than 5 days from being an elder the Try For Baby option no longer shows up.  However, if you have built up enough Aspiration points from fulfilling their wants, you can go into your Aspiration Rewards and you'll find a Green Water Tank that is called the Elixir of Life.  Make sure your sim is Platinum when they drink from it, and it gives them back 3 days for every drink, and I believe there is a total of 5 drinks from it.  So that's 15 days you can get back for your sim.  Only your Female needs to be 5 days or more away from Elder, the men can make a woman pregnant even if they are an elder, much like in real life lolololol.