Mom, can you please help? My daughter started holding her pee, she goe…

Mom, can you please help? My daughter started holding her pee, she goes in diapers during the day while sleeping and they say at daycare she pees on the potty, but at home she seems to hold it back. When we come home from daycare, she sometimes runs into the hallway and holds onto her panties and cries, I quickly take her to the potty (where she usually goes to urinate) and sits down, and nothing happens, maybe for 20 minutes sitting and nothing, either alone with me or then again the same thing until night! Does she pee in her diaper at night too? Is this progress? What's the next step to take? Does holding it back harm her?