I had the same issue when I was far along with my pregnancies…with my son I lived in a house that was very old…in the hundreds…it had no insulation, no foundation and it was falling apart…I had a very bad mildew problem as well…when the baby gets bigger you loose space in your body…the baby will often cause your lungs to be compressed, I was sick and had mildew in my house so I suffered really bad…I talked to my doctor and he just told me to keep him informed on how I was feeling and to get fresh air often, if I could to stay somewhere else until the baby was out…I was sick for like the last 3 months of pregnancy no matter what I took…my lungs were compressed because of the baby and it was keeping my sickness trapped in them, just make sure you talk to your doctor and keep him/her in formed on how you are feeling…I hope this helped…Love Meg