So short of breath- advice?

Davesgrl2011

All day today I've been short of breath- to the point sometimes that I feel like my heart is racing or pounding from lack of oxygen and I start to feel overwelmed and panicky.  If I lay down it is definately worse, but it is still bad if I am sitting or standing.  I tried stretching and taking calming breaths... but I just feel like I have to really concentrate on breathing.

I've heard that when the baby drops I will be able to breath easier- but I am only 33 weeks.  Is there anything I can do now to help me take more consistantly deep breaths and get more from the air I breath?  Is this something I should be worried about?