this shortness of breath is annoying!!!

La
I have such terrible shortness of breath. Been sitting down for a few hours now at work and I just cannot take a deep breath. Wth!! 
Last night I couldn't sleep because of it. Every time I dozed off I gasped for air and woke back up. 
What can I do? Usually if I wasn't pregnant I'd take a Xanax to sleep and call it a night. But I obviously can't do that. 
I'm 17 weeks today. Any advice would be helpful because this inability to take a deep breath is bothering me.