Try not to freak out too much :)
My son had that same issue when I was pregnant with him. They had me worried SICK that something was wrong with him. Turned out to be small calcium deposits. Now that sounds bad, but I was told that they are more common than people think and they disappear on their own. Basically the calcium gets absorbed back into the body.
As long as your blood tests come back fine, You ARE FINE. and so is your baby.
My son is 2 and literally has NEVER been sick. You're lil one will be fine.
OH don't let your dr. freak you out and make you think you NEED to have any surgeries done to "check it out"
You do NOT need an amniocentesis, those can be more harm than they help :)