You are probably under subconscious stress
. Your symptoms do suggest that a possibility of pregnancy is there.
The pain between the shoulder blades is may be due to heart burn if it is severe and if acid is coming into the lower part of your food pipe. For this try to avoid fatty and spicy food, try to sit upright, take small frequent meals and plenty of water and cold
milk. if it is severe. This may happen during pregnancy too.
Regarding the pregnancy, get a urine pregnancy test done as it usually comes positive a week after the missed period in women with regular cycles.
So go ahead and best of luck!