Last night when laying down to sleep i felt sob but fell asleep, then woke up 30mins later very sob and fast heart rate. why? i'm 23 weeks preg.

Can be normal : Shortness of breath can be normal during pregnancy due to a combination of hormones and upward pressure on the diaphragm from the growing uterus. However, things like blood clots that travel to the lungs are also more common in pregnancy. Your symptoms warrant evaluation by a medical professional who can check your vital signs and probably provide reassurance.