Toddler regression?

Okay so I have a 3 year old boy and 2 year old girl and I'm 19 weeks pregnant with #3( boy) For about the past two months my kids have really been acting out. My boy especially used to be the kindest most gentle little thing and he's been talking back and aggressive lately. My daughter who always calls me mommy, has reverted back to calling me "mama" like she did when she was a baby, and barely talking. She barely makes use of her words and now points to things and makes sounds when she wants something. I kno she is two and she is a baby but she is acting like a BABY BABY. I saw an article about toddlers regressing while mom is pregnant because they can sense change? The article said to just give extra love and cuddles so for now that's the attempt im making...... Just wondering if anyone else has experienced anything like this?