The liquid part is easy, we're mostly liquid. The hard part is why this is happening, and the only advice I can give is, if your urologist isn't helping get a better urologist. At your age, you should be able to drink anything at any time and not do this, although when we get old both men and women can have this problem. So something is wrong, but as to what, can't say. Many people have weak bladders for many different reasons, but for most it means they have to go a lot. If it only happens when you're sleeping and not when you're awake, that's a different matter. But as to the liquid, that's what you're made of. Drinking gives us a form of hydration we need to have but even when we haven't drank anything recently our bodies are still mostly liquid, but we don't usually have to go to the bathroom until we get old and things don't function as well or we have surgeries that affect us or we have problems that impinge on the bladder. Children wet the bed for various reasons as well. If you don't know why it's happening, you can't really fix it. Those drugs are for people with overactive bladders, but they have problems when they're awake as well. If it is psychological, it will take more time to find out why, but I wouldn't assume it is just because some doctor said it was so he could get rid of you. But, you know, it could be.
It's important to know you aren't alone. There are other adults that have this issue. https://www.webmd.com/urinary-incontinence-oab/bed-wetting-in-adults Have you ever tried setting your alarm to train yourself and you bladder when to release? That's something a lot of parents do. There is also the bed wetting alarm systems to help train you to get up. I'm glad you are seeing a doctor for help with this. There are good meds now for overactive bladder but am sorry the two you've tried haven't been effective. I would continue to push for answers and help.