My sister in law has me all paranoid about going into preterm labor (she's had a bad pregnancy and wants mine to be just as bad.) My job has required me to be on my feet for several hours, in a hot warehouse, lifting, and constantly bending over. I'm almost 23 weeks. I've not really been in pain, but there has been a couple times where I'm pretty sure my belly has gotten harder or tightened for a few seconds, I've had a backache for about a day now, and I'm nauseous again. Should I be worried I'm going into preterm labor or am I just paranoid?