Almost halfway through and terrified

You know last time I was in surgery I almost didn't make it out..That is when they told me I would be unable to conceive ever again.And now I'm almost halfway through (19+4 to be exact) and I am terrified even though I know I should stay positive its all I think about. Last time I went in I didn't think I would have almost lost my life and now to think I can possibly leave my babies behind scares me. I know I should be excited to be blessed with a third child and I am completely ecstatic but can shake this feeling..Sorry needed to vent without worrying my family..