Over think and over worry too much

Im 22 weeks pregnant after 2 previous miscarriages and this is by far the farthest ive gotten. The doctors say hes doing really good and hes moving a lot and doing perfect! However, im still terrified something bad will happen or he will be a stillborn or something else at the kast minute. Its kinda freaking me out. Everyone tells me to relax and hes doing perfectly so dont worry so much but I am just so afraid something will happen. I finally let myself get excited and happy when I was 16 weeks along. I dont want to have my heart shattered again...