Toddler poo help please!

My 2.5yr old is fully potty trained in the day and 90% of the time wakes with a dry nappy each morning. Our problem is her pooing.

She used to poo daily, sometimes twice. Since all of her wees have been on the potty she works herself up so badly about pooing. She holds it in for 3/4 days and then eventually has to let it out but she gets so worked up and upset.

What can I do? We try and give her the typical foods to help things move along but I think she’s so wound up she just continues to hold it.

She tells us she needs to poo multiple times a day but when we encourage her she freaks out.