pelvic pain and pressure

Katey
I am aslo 26 weeks and 5 days pregnant and when i stand or walk a lot for a while,i feel some mild pain in my lower pelvic area and back pain. It was so difficult for me now to stand from the bed. I'm working as a nurse so alot of walk im doing everyday. i am scared and worried if there might be anything wrong as this is my first child.The pain last for a while and once i rest it cools down. The pain is still mild still tolerated but it keeps me alarmed on it. Some research pelvic pressure or pain is due to dilatation or increase the size of my uterus. Any suggestions what to do to relieve this pain. 
Thanks 😀