You can test yourself but will need a number of cups / jugs. Each time you get up in the night, wee into a new jug. Tomorrow morning, measure the content of each jug or cup in turn in a proper measuring jug.
A normal bladder can hold between a third and half a litre of urine. Are you passing half a litre every time you thought you were bursting?
For John, the penny dropped while camping. He keeps a small juice bottle in the tent rather than having to go to toilet block in the middle of the night. Took a while to realise that even if he got up 3 x a night, the bottle (one of those 330 ml Oasis bottles) was still not full the next morning. His mind was telling him he was full when he wasn't.
You can get bladder re-training from your local incontinence clinic, usually via a GP referral.