See picture for semi relevent. Also, I've had that same kind of dream - see, my mom got pregnant. I was pretty young, so I don't really remember. I can't say I had the guilt thing going, because mom had to tell me for me to know any of it.
She told me that she'd felt sick, so she went to see a doctor and said "I think I'm pregnant." She was on birth control, and the doctor insisted she wasn't pregnant, and prescribed her pills. They went through nearly ten different prescriptions of various experimental drugs, trying to fix mom's morning sickness and nausea. After a few months her doctor said "Oh, my bad, you were pregnant after all. But due to all those pills we made you take, the baby is dead. Sorry about that."
I'm sure they really were sorry but... It would have been nice to have a younger sibling. I always wanted a little brother - I cried so much when mom told me I almost had one. My older sister moved out a year or two before my parents started fighting. It would have been so nice to go through that with someone by my side. I was all alone.
I've dreamed of meeting him. He's barely three years younger than me. He tells me things like "You aren't alone," and "We would have gotten along," but I'm sure it's just my subconscious.
Sageing for tl;dr boring post.