Working while pregnant

Ginny • Hello I'm 25 and loving my life. We are expecting a little boy and I'm in love with this baby.
So far it's been ok working full time standing all the time with occasional breaks. I have been working a little too hard and feeling it by cramps and back ache. I was the person the worked there butt off and have to keep reminding myself to take it easy. My doctor wants me to work till birth but things are getting harder and rough on me. Any one experiencing the same ?