Constipation

Hey ladies, so Today I realized it had been 3 days since Cecilia last poop.
We where at preschool today and she was (more) horrible then she usual naughty self she was crying and being mean to everyone!
Well by the end of the day she hid to go poop she was shaking and crying because it hurt so bad. Her poop was hard and runny at the same time. Not sure if that matter or not.
My question is will constipation make her really grumpy and feel sick almost?
And what things can I do to prevent her from getting constipation, and what can I do next time i realize she is.
this will be a post and run. I gotta go to my bday dinner  

My daughter is like that when she is constipated as well I give her apple juice it helps a lot n she is back to being the usual mean self not a monster anymore

Thanks Jessie!
Is there anything else that helps?
Cecilia doesnt always like juice.

I havent tried anything other than juices sorry