At 100ml my bladders irritated&wants to be emptied, but I sleep through the night and can hold it. It doesnt hurt when I wake up. Whats wrong?

Bladder irritants. If you haven't already, see your doctor to rule out a urinary tract infection and a condition known as interstitial cystitis that can cause the symptoms you are having. In the meantime avoiding certain foods and drinks can help. Here is more info;