"Take my Breath Away"

I have been having the hardest time breathing lately! I can be standing up doing NOTHING and all of a sudden have to lean over and gasp for air. I sometimes feel like I have run a marathon after giving my students directions on a worksheet and will have to sit and focus on deep breaths. It hits out of nowhere and usually when I sit it can get somewhat better, but it happens when I am sitting sometimes too. I am not sure if it is just the position of the baby pushing against my ribs and lungs (I know they do that). It's very uncomfortable whatever the cause. I'm not trying to be a whiner...although I am pretty good at that. It is just hard to function as a K teacher especially during Achievement test week when I have to read tons of oral directions and walk around to monitor my kids....I got through #12 yesterday and gave up..I had to sit. Luckily my aide came in to monitor today while I read. I still have 27 teaching days left and I want to push through till the end, after all the baby is not due until the end of June. But is oxygen too much to ask for???? I put in a call to the doc just in case. I am likely to blow things off as nothing, but I guess a phone call can't hurt and everyone said I need to at least make him aware. So, I am waiting on a call back......hopefully this baby will change positions soon and give me some relief:)

UPDATE: Doctor ordered a stress test. I'll go take it today..I'm sure everything is fine though.
UPDATE 2: Did the stress test and everything looks great with me and baby. Guess I'm just going to have to get used to less air for the next 9 weeks:)