Hi there,
I am so very sorry for the loss of your precious baby girl. I can only imagine how hard that is... At the same time, I personally think it's a good sign that you are giving thought to "What if I have another child" because it shows that your pain hasn't made you bitter and giving up on life!
I agree with you that it doesn't seem right for CPS to get involved solely because of a mental illness. I also know that at least for me, many of my worries and fears don't come to pass. Do you think that could be true for you? I also know -- at least here in my state, CPS workers are pretty swamped with work, AND, it takes a LOT for them to take a child away from a parent. But I understand your fears as I had them too when I wanted to have a baby.
I have been hospitalized multiple times for major depression, anxiety, ptsd and suicidal thoughts as well as several tries. Do you have a therapist you see regularly? Maybe he or she could be of help in this area regarding the probability of your fear coming true.
Personally, I think you have done everything right, everything you CAN do to put plans in place for self care. You sound like you'd be a responsible, loving and protective mommy who has the insight to know what your symptoms are and would ask for help rather than put a child at risk!