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