Is it your growing baby bump or asthma causing the problem do you think?
If you think its asthma and your inhalers are not touching it or keeping it at bay then you need to go see your GP and possibly increase the dosage of them (brown or purple ones). Your GP can tell you what dosage you can go up to safely. Once you reach this and if you are still having problems you'll need more aggressive treatment possibly.
I use a purple one (Becatide) morning and evening and have a brown one that I used to use and use when I get asthma problems that don't go away. I can max out to 4 puffs twice daily of that. If that doesn't stop attacks from happening I need to see my GP and get a course of steriods. I also have the blue one for when I have an attack and need to take something during it, but the whole point of the green and brown inhalers is that the use of the blue one should be minimal.
If its not asthma related it may be as others have said that baby is pushing against things internally and causing breathing woes, but this is a normal thing and not much to be done there. Sleeping more upright might help.
And I really notice it when I'm singing - my insides are all sqished and there's no where to put air!
