Ok I have two little one at home. I am a stay at home mom two days a week. I love this. I am newly pregnant

, I am so excited, but so very scared. I have had 3 very painful miscarriages and I worry so much.
Here is my question I have to lift my little ones, especially when I am the only one home. It is lifting into the highchairs, lifting into cribs/out of cribs, over gates etc.....the list goes on and on. I am now worried that I killed our baby from the lifting. I called my nurse and she said that it is just a guideline and to take it easy. She said that is shouldn't cause miscarriage just more back pain. I think she was tring to make me feel better. I am looking for some honest answers here.............what do I do to not continully lift children? What damage could I really do this early in the game? Do you think it is too late. PLease I am near tears here.