H.W.
First, good for you for finding a good counselor. So many people are afraid to do this. Keep up with this person.
I, personally, think that this fear is something you should stay in touch with your counselor about, and do not play it down. If things are feeling really scary, then it's good to share this. The counselor will be able to help you differentiate if this is situational (and what a situation, I am so sorry) or if there is an post-partum depression/anxiety at play.
Speaking from personal experience: some things that happen to us in life feel very scary to us, and our level of fear is our survival instinct kicking into gear-- it is appropriate to the situation. In previous years, I have had to work through my PTSD with the help of a counselor. PTSD isn't an over-reaction to what happened to us, it is however the brain's response to what happened to us, and its desire to keep the body safe. Knowing what your triggers are really helps to make those feelings more managable. The sick-to-your stomach feelings sound like anxiety, and I'd talk to a naturopath regarding what you could do to make this feel more managable, esp. if you are nursing. (This is also something I've dealt with, anxiety.) I've found herbal remedies very helpful, so naturopathy is another route to look into.
I appreciate your love for your daughter, and your desire to be protective of her. The good part of this is that you are addressing these fears now, so that they won't inform all of your parenting in the years to come. It's scary to see our kids as they take risks and learn so many new things, sometimes, but we have to let them take reasonable risks. Continuing with your healing will help you be able to do that.
And if I can be bold and recommend one book for you, I'd choose Bruno Bettelheim's "A Good Enough Parent". It was very helpful and an eye-opener for me. Good encouragement for us to be brave and strong for our kids.
My best wishes go to you.
H.