I wasn't particularly bothered by the work-in-progress rivers beyond the things like the loop in the middle of the river. Lack of sleep is a powerful force in the world, and rarely for good.

The simplest way to get your rivers in the right place is to figure out which parts of the world are higher than the others. Water than flows downhill via the steepest possible path. Over time, the water will erode land to make channels, which will join together into a single channel if they get close. Bigger rivers do more eroding and capturing, making rivers join together on their way from the high places to the low places. It's the eroding and capturing that causes effects like lakes having a single outlet, rivers not running parallel, rivers not forming loops, and rives flowing from one ocean to another.

Another way to look at it is that rivers are ways to dissipate gravitational energy in as efficient a way as possible. The sun provides energy to evaporate water and lift it up in the gravitational field of the planet. Rain or snow then puts that water onto the land. The water then moves downward as quickly as it can, doing as much damage to the landscape as it can manage. Water high up on mountains can pretty much go down the mountain quickly, letting it erode fairly straight and deep canyons because that fast-moving water can move a lot of stuff. As water gets out of the mountains, it slows down, dropping a bunch of stuff (which is what the not-mountains are generally made of). When the water gets to really flat areas, it still has energy that it needs to dissipate, which it uses to cut side-to-side, which causes meanders. When the water gets to a low point like a lake or ocean, it can't go any further down, drops everything that it's carrying, and mixes with what's there, doing no more damage to landscapes.