Toddler misbehaving because of pregnancy?

J

I've heard alot that kids know when their mothers are pregnant. I don't know how true that is. But my daughter who just turned 3, lately has been so bad. Very cranky, throws tantrums, lashes out. It's not like her. Sometimes she's sweet and kisses my tummy out of nowhere. And she rubs it , and says baby (as we took her to our 10 week appointment and she saw the baby) . She isn't sick or anything I just notice she's been acting up ever since then. I am now 12 weeks.

Any advice or a share of experiences would help. Thank you girls in advance.