Out of breath “overnight”

I feel like Baby Girl just got so much bigger over night! I know it doesn’t really work like that but I swear in the last 24 hours it’s gotten much more difficult to feel like I’ve gotten a good breath. My tummy is feeling more firm and I noticed a heavy feeling in my pelvis when walking around. I was also a bit more nauseous today for the first time in a month and a half and this heartburn just won’t quit. Anyone have any experience with symptoms like these? This is my first pregnancy and I just hit the 26 week mark yesterday.