Behavior changes

My daughter turned 3 in august n it’s like a switch flipped. She’s always been clingy and sensitive but everything makes her cry now and she’s constantly whining about things even when they make her happy it’s whining. She’s a happy kid most of the time so it was unusual for her and I tried to see if anything changed but nothing had. She got clingier when I got pregnant again this year but as it gets closer(30 weeks) it’s so much and part of the time I just need her not up my ass for 2minutes😂😂 I love her to death and love that she’s sensitive and is very observant to emotions with everyone but I can’t tell if it’s because I’m missing something she’s needing or if she’s just picking up on things or what but the whining and crying over everything is getting old very quickly and honestly frustrating.