How did you know your child had diabetes?

Idk if this is normal or not but when my 4 yr old is hungry she is beyond HANGRY. I always try to make sure she’s on a good eating schedule to avoid any tantrums. This rarely happens with me, but when others watch her she doesn’t always get food on her schedule. She’s a well behaved child but when she’s hungry she’s a totally different child. She screams, kicks, sobs, and is just plain mean to anyone when she’s hungry. Is this normal for kids this age? Is this a sign of diabetes? Wasn’t sure if this would be worth bringing up to his doc.