Any idea why? Is it that he is afraid you will miscarry again or is he upset that you didn't tell him sooner? Maybe he equates you being pregnant with the time you were in the hospital and is worried you will be sick again. It's also possible at that age that he is embarrassed that mom is having sex.

Best thing to do is ask him. Tell him you are worried about him and want to know what is bothering him. If he won't talk to you try having a grandparent or maybe a favorite uncle talk to him. Teenagers have very active imaginations so he is probably scared that something will happen to you.

Are you married to your son's father?

Well he did state at one point I did it to replace him, and no I'm not married to his dad we've been divorced for years.

That's your answer. Your son thinks this baby is to replace him. Not uncommon for older siblings. Are you remarried? How is his relationship with this baby's father?

Somehow you need to find a way to get your son involved in preparing for this new baby. Maybe helping get a room ready or with shopping for clothes and stuff. It's tough with a boy since generally they aren't too interested in that stuff.

In the meantime try to be as normal as possible. Your son is probably feeling left out at this point. Make sure you spend as much time with him and on his activities as possible. Avoid making everything about the new baby.

He's suffering from the "what do you mean I have to share my parents with some "upstart" syndrome!

You'll just need to show him that the baby is not someone who will take his place. Just another addition to the family.

Are you remarried?

He may be feeling threatened by the new family since his old one is defunct.

My daughter at 9 has no issues whatsoever with her 2 year old baby brother with my new husband. I told her that I wanted to give her a new family at his household. That I needed her help. That's she's Little Mama. (Not that I gave her tons of responsibilities, though.) Now, she's totally proud and beams with self confidence when she's able to care for him.

Maybe get him to buy in by saying that this will be great practice if he marries and has a family one day. Give him some ownership in this. It's not something that happened "to" him, it's happened with him in mind...

I think a lot of it depends upon the father of the half brother... Where's he in all this?

Not remarried yet there are circumstances that are holding back, though he is around trying to help. I am trying to keep things normal and yeah he's a stubborn one.

Well, that could explain a lot. Maybe he's not liking the father of his half brother and feels like you've chosen your sexual partner over your own son.

I think that some of what he is feeling is quite normal and that he will adjust in time.
This is a nice time for the two of you to spend time together once he gets over the initial shock.
Including him in as much as possible should help--buying things for the baby, choosing a name etc..
If his own dad is involved maybe he could spend time with him too.
Sounds like he just needs to feel secure, loved and safe.
He will be fine and I would just make sure that he knows that you are confident that he can adjust to this change and that you will be there for him once the baby is born. Congratulations

Could it be that the father of this baby is not a good guy and your son's right to be concerned? You say he's stubborn and there are "circumstances." Kids may be young, but sometimes, they are very wise. You never can go wrong with asking your son to talk and promise that you will listen and not comment back. It's difficult, but if you promise that and just say, "Thank you for sharing and what can I do to help," it's amazing what they will tell you. But you have to treat what they say with great respect and tender care and never use it against them.

Why is he upset? Is he worried for you or is there something you are not saying?