It sounds pretty typical to me. Preschoolers are just learning to manage themselves in a group situation, and they don’t know where the boundaries are. It’s the primary job of a preschool teacher to help kids learn the rules and how to keep their hands to themselves. A preschool director friend used to tell parents who were pushing academics (teach 3 year olds to write and to memorize the state capitals, for example) that the purpose of preschool is “to teach them to separate from Mom/Dad, sit in a circle, and negotiate their own space.” Period.
So, this boy is fascinated by your daughter, he doesn’t know what he’s doing, and she doesn’t know much more. Normal. You can talk to your daughter until you’re blue in the face in the evenings and on weekends, but nothing will be more effective than the teacher intervening at the moment the problem occurs. I can’t see how a therapist would help at all.
I wouldn’t discount that your daughter is picking up cues from you about your pregnancy. You’re tired, you’ve probably just about had it, right? You’re probably talking to her about the baby to come, and she knows, even on her level, that things are going to change. That’s a bit unsettling.
Moreover, she’s just learning about preschool, and the newness has worn off and she’s getting the idea that this is all the time. It’s only November and she’s got a lot of maturing to do. She’s learning to listen to a 2nd person and to separate from you. Sometimes that ticks kids off and they become disrespectful. She’s also hearing the mouths of other kids, who are picking up all kinds of things from their older siblings, so she’s going to bring home some gems from now through 12th grade. (Wait until she gets on the school bus with some third graders!)
I think you can talk to the teachers or ask for an email about what sorts of phrases they use to get your daughter (and all the kids) to comply, and consider using some of the same language. That way, kids learn that this isn’t “Miss Laura being mean” or “Mommy being mean” but rather “just the way things are.”
I also am concerned that you have no idea what to do. Try some parenting classes and get some great help from experienced parents and teachers/trainers. You can get some infant/toddler first aid, which is very valuable, and learn about the different stages in child development. You will really benefit from being more confident in your parenting philosophy and strategies, and in learning how to prioritize what’s urgent and what’s just an annoying and frustrating phase.
Good luck in these next few weeks – wishing you an easy delivery.