Feeling weird today

Nancy • My daughter Ava Grace is my world! 05.04.16 Expecting March 2019
I'm feeling weird today! I'll be 34 weeks tomorrow and I just feel exhausted, legs are giving out, stomach feels so hard throughout the whole day, and just feel uncomfortable. Is this because I'm getting bigger? I just don't feel like I have energy at all, which is very odd because I been on my feet everyday and working, with full energy! 
This is a picture of my stomach today - 33weeks6days