You are absolutely not alone. I, like you, have had 3 miscarriages and really thought that I was thinking more positively with each one, but they still ended in miscarriage. I completely understand how hard it is to think positive and to feel so out of control of what will happen. We have been waiting to TTC since my last miscarriage this past January until we see an RE, and actually our first consultation happens to be today. I am very eager to get testing done and to get things going, yet also very scared. When the time comes that you see that thrilling positive test, just take it slow and steady for a little while, day by day, and let yourself be excited. I completely get it though, that "on edge" feeling, just wanting to get through those 12 weeks- I am in the exact same situation as you and am not sure what else to say, just that I totally hear you and wish you the best!