You have reached a milestone, and I am sorry.
A few short weeks ago, you had little in the way of separation anxiety. Mommy or I would put you in your crib and you'd mewl for a minute, maybe two. After that you'd think, "Oh, what the heck? I'm tired. Might as well go to sleep and not bother with all the noise."
And that was that.
Now, not only are you aware of being left behind, but you know all too well what happens to Mommy and Daddy at bedtime. You are aware that after laying you down, we exit through a door. Maybe you always saw this, but now you realize it.
Therein is the difference.
This new consciousness, combined with your recent attempts to crawl, has led to a wonderfully sad, heartbreaking period for you.
The other night, I placed you in your crib, and you were unhappy.
I gave you a kiss on the forehead and stole out of the room expecting the usual scenario: a minute of crying, followed by the silence of slumber.
Except after two minutes, you were still crying.
Same with three minutes.
Same with five minutes.
I tiptoed back to your room, gently cracked the door and peered in...
... and you were not where I had left you.
I had laid you down with your head facing away from the door, on the far side of the crib. When I checked back in, you were sitting up, at the corner of the crib, right next to the door. You were so sad about being left alone that you moved your little body to the last place you saw Daddy.
Once there, you were trapped by the bars of your bed. All you could do was grasp them and howl.
Of course I immediately opened the door wide, stepped in and reached down to scoop you up. You instinctively grabbed at me, clawed at me, signaling your need for contact; Daddy's warmth > the empty crib.
Even though the door Mommy and Daddy exit through is a new discovery, you've been aware of the difference between your room and the outside world for a while.
Sometimes, if Mommy and I would carry you into your room for nap or bedtime, you'd start to fuss. You knew what was coming, and wanted nothing to do with it. If the fussing turned to a full-on tantrum, the mere gesture of bringing you back through the door and into the hallway would end your tears; they shut off as if by spigot. You know the difference between your bedroom and the "social rooms" of the house. In your bedroom, you're left behind. In the living room, there's action aplenty.
Usually, that second burst of love is all you need. Ten more minutes hanging out with the family. Five extra minutes of smiling at your sister. Three bonus minutes of flailing at our doggy in an attempt to pet him. It's a reminder that we are always somewhere close, and that you're never truly abandoned.
Soon you'll pass the milestone where you don't even need that, and will understand that you are always loved.
Even when we're not in the room with you.