Did your Doctor specifically tell you, do NOT lift anything "heavy?" if you are pregnant??? And if so, what is the weight limit?
Generally speaking, yes, the generic 'rule' while pregnant is not to lift anything heavy, and certain circumstances, like yours (being in the wait period before finding out your status), is naturally more sensitive.
But I would simply ask your Doctor, per your situation.
All us Moms, who were pregnant with a 2nd child, can't help but "lift" our other child, while pregnant. I know I did... but again, I was not on any restrictions. BUT... if you have extenuating circumstances whereby you absolutely cannot lift anything heavy... then you can't. I know your girl is only 19 months old... but if you are medically directed that you must NOT lift your child, then you shouldn't.
Try using an umbrella stroller in the house... and wheel her around. THEN, you can hold her, but while you are sitting and on your lap. If your girl wants to be held while your are standing up... then you have her stand on a sofa...while you stand facing her, and "carry" her that way... but without her actually being "carried."
Children, can adapt most times... and she may very well understand in some way, that you "cannot" carry her right now.... but there are alternatives.
If your pregnancy is normal and you don't have to limit your activities... then rest assured. Just ask your OB/GYN. Its hard for a Mom to COMPLETELY 'not' carry their other child for 9 months.... Unless you have to, AND you have a helper with you at all times.
All the best,
Susan