Maternity clothes fit

Crystal • Married for 5 months together for 7 years, pregnant with baby 1. Scared to death!
This is so frusturrating. I got pants in a size smaller then I normally wear but the shirts in the size that should for me are way too tight and I'm not talking just in the stomach area, in the arms and on my back as well. Is there some trick I'm not getting or something?! I have no clothes to wear!