OP, I feel exactly the way you do at times, right now happens to be one of them. DD is an optional now, the hours are long, the coach is tough, the skills are big, and the drive is killing me. DD misses out on sleepovers, play dates, etc and sometimes I wonder to myself, what is this all for? Where is she going with this? I cannot answer those questions because I have no idea where this sport will take her. BUT it is her passion and the mere mention of quitting or finding something different sends a look of horror into her eyes. So I could never take it away from her. If she ever wants to quit it needs to be her decision totally with no suggestion from me.
When I get really stressed over everything, I try to remind myself how quickly those toddler and preschool years were. I blinked and they were gone. And this stage in life is likely to be the same. In the grand scheme of your life, this is a very short period of time that you feel like you are running around like crazy. And even though we may ask ourselves what this is all for, I can promise that our girls do not ask that question. They know that the point to all if it is that they LOVE the sport and can't imagine themselves doing anything else.
Before we know it, we will be looking back sadly on the days that we used to cart the kids around, make their dinner and snacks, and talk to them about their day on the way up to the gym.