Constipation. Why is she unable to poop?

My 2.9 yrs old kid is facing constipation for past 1 month, which is in an unusual way. Earlier, when the constipation occurs, it would be little tough for her to push but she ll do everyday. She did not suffer too much. But now, it goes 3 days without pooping but she is getting the urge to pass motion every now and then. Instead of trying to push, she is pulling it inside and keeps walking with her toes and cries all day with pain. Unable to sit or bend. Not allowing anyone to touch her. Food intake also became less. She takes veggies n fruits and fibre rich food is included already. She doesn't take junk food too. Now, she seems to be afraid of pooping. Suppository is given twice already.. laxative laxopeg is prescribed for a month. Is it ok to give it for months time? Will she become normal soon? When she is getting the urge to poop everyday, why is she unable to poop? The stool looks dry n hard n bigger(than usual) in size. Kindly clarify.