A few questions for you...

Hi, I hope you all can help me. I am 7 months pregnant. Lately I have been feeling short of breath. I am not cyanotic and my SATS are good. I feel like I cannot get a good breath unless I yawn. It is not all the time, the first time it happened was about a week ago, and lasted 2 days and then I felt fine, but when it does happen, it lasts for hours and last night I could not sleep because I felt this way. I would feel better after a yawn for about 5-7 minutes and then it starts all over again. I must have yawned 75 times and I felt this way all day. I feel breathless when talking to someone for a long period of time. I understand everything is being pushed up. I guess I am feeling anxious because I feel like I can't breathe, which makes things worse, I suppose. Is this a normal thing in pregnancy and can you help with things that may reduce this feeling? Thanks for any suggestions you may have.