Hello! When I was pregnant, I experienced breathless quite frequently even till I blackout.. i can even wake up seeing myself sitting on e bed.. Went to Cardiologist and lung drs to check and all my results were good.. It shld be due to my organs are trying to make some space for baby, especially e stomach..
I am 7 weeks now with number 2 now and I stop breathing from time to time or the same experience as you..will only get to ask doctor in 5 days time...