Is it normal for people to see your facebook message and not reply?

[Gabrielle]

Yes, this is normal. Many people behave like this. It is common in the Facebook world.
Multiple things could have happened.
One, the person may have "seen" it, but that does not mean they read it. Different scenarios could have happened. Perhaps the person was busy and glanced at it before closing Facebook. Perhaps, they read it but then was short of time and was not able to respond. Depending on the question, the person may have to think about it before answering. Many things could happen, do not worry. It does not mean these people care less of you or do not care for you. You may not completely understand the scenario. Trust me, and move on. Life happens.