Pressure/heaviness and shortness of breath at 27w? help!

I'm 27 weeks and now as I try and try to get comfortable in bed I'm feeling a lot of pressure/heaviness in my abdomen. It feels like someone is sitting on my stomach. It is so uncomfortable that I'm finding myself short of breath. I'm not sure if the feeling I'm having in my abdomen is bloat? Ive been having awful heart burn the past couple of days! I don't remember having this pressure in my belly with my first. Is this normal or cause for concern?