You hadn' known the plan. The plan that included Sam jumping into the cage with Lucifer. Because if you had, you would have talked him out of it. Both Sam and Dean kept it from you. Because they both know you wouldn't have let Sam do it. After all, he was the love of your life. You didn't want to lose him like that.
But you had anyway. You'd lost him.
And little did you know that before he jumped, he had gotten you pregnant just a month prior, and neither of you had noticed the symptoms.
But you eventually had. That's when you realized you couldn't just sit around and grieve. So you stopped hunting. Just like Dean. You went your separate ways. Dean went to live with Lisa, and you went to live with Bobby, so you had someone to help with the baby when it came.
And then a year passed. You had a healthy little baby. Sam's baby. That child was the only thing that truly kept you going. The only little piece of Sam you thought you had left.
But one day, Sam and Dean showed up as Bobby was out. You were bewildered. Dean explained the situation and all of it with Sam being... soulless. He'd been soulless and ALIVE...
As Dean was talking to you in the kitchen, Sam heard something upstairs. He then turned and snuck off, the soulless man now heading toward the soft noises from the room upstairs, down the hall...