I think I read that we're supposed to spread water consumption throughout the day to better benefit our bodies. But as Sumi said, you could stop a couple of hours before bedtime. As Marti said, each body is different, but in my own personal experience, the urge to go lessened considerably after about 2 weeks. So just hang in there.
One other thing - eighty ounces of water daily seems like quite a bit. Since I'm not a health care professional, don't take my word for it, but maybe you could ask your doctor what amount he/she recommends. The answer may depend on your current weight.
Btw, you can come on into the Weight Loss and Chitchat thread, if you'd like. We discuss all sorts of weight-related topics there, plus daily chitchat, too. You'd be very welcome to join us there.