I'm not a dream interpreter by any means, but I was taught to interpret my own dreams. It seems obvious to me that you have deep feelings of inadequacy and loss of control. The dreams about your children may just be a manifestation of those feelings or your subconcious is trying to tell you something about your children. It doesn't mean that you might lose them, but it could be that it's your greatest fear.
My feeling on this is that you need to do things for yourself that would increase your self-esteem or self-assurance. This would be all personal work. You're probably already a very good mom but the more you become a whole person sufficient unto yourself, the better your kids would be.

You would pass those additional qualities on to them.
<font color=blue>"Our doubts are traitors and make us lose the good we oft might win by fearing to attempt" --Shakespeare</font color=blue>
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.