Why does everything feel so fragile?

Does anyone have a cure for gloom and a sense of impending doom? In my heart I know that God is my hope and His sovereignty over my life and all of creation should be enough to dispell these feelings. But, my head won't get it. I keep wondering when something else will go wrong, when the next piece of bad news will arrive. The welfare of my family and myself seems always to be at risk. Millie is currently dealing with a spider bite and some diarrhea. I'm worried that my dietary measures and comforting her is not enough and she is going to become deathly ill. It's usually a fleeting thought, but it's there. My breasts feel lumpy and sore, but that may just be because my milk hasn't completely dried up and I am still returning to unpregnant "normal". Perhaps the bras I'm wearing don't fit right at this point. My mind keeps pinging to words like cancer and masectomy. I have nightmares about something happening to Royce or my parents. I'm fearfull of someone breaking into our house. Why am I so fearfull? I believe that God loves me and is in control of my life. I trust Him to do what is best for me. Perfect love casts out fear. What's wrong with me?
I feel a sense of failure about the pregnancy and about Bryce. Not that I conciously did something wrong, but more that my body failed or just a general sense of failure. I want to give my husband children, and losing Bryce fails at that in a sense. We want children, to raise a bunch of kids together. My reproductive system does not work like it should. My OB/GYN diagnosed me with PCOS due to my irregular periods and other factors. I have to take fertility drugs to ovulate in order to get pregnant. Hopefully someone will discover a cure for my condition, find out how to get my reproductive system functioning normally. Wishing for things doesn't make them happen though. My prayer is that God will enable me to trust him with this and every other area of my life. He loves me and wants my good. Only He knows exactly what that looks like.