What you're describing doesn't sound like a problem with your job per se, it sounds like depression. You might consider consulting a professional before making any life-altering decisions. Good luck to you, whatever you decide.
A good therapist would probably talk you through all of this, but look at your own self-talk first...
Your core belief is that you don't think your career path is going anywhere. If that is a rational conclusion you've reached then of course you'll have little motivation! In fact that's pretty damn normal, who else do you know will continue to enjoy a task they genuinely believe to be worthless / dead-end?
My big worry is that I don't figure anything out...
You will figure things out. Take it a single day at a time. You can only move the mountain one stone at a time. In fact I would say take a good 2 weeks off to just say "I don't care" to the current job and go do some _relaxing_ travel. See what 2 weeks gives you, 1 week isn't enough to totally disconnect. When work sucks, start squeezing the joy out of other areas of life.
Depending on your situation, you may just be in for some life changes. I had a period of time about a year ago similar to what you described and I'm about your age... It was a large mix of things, but my own bullets may stimulate your thinking...
- I gave up the whole mega-startup goal, I like doing smaller projects now with no care about huge exits
- I reconnected with friends and now focus more on relationships
- Stopped going on the computer once I got home from work and just doing more work. Going on the comp at home is now when I have nothing better to do, which is plenty.
- Temporarily changed lifting routine to light cardio for stress relief
- Got outside more.
- Rode the motorcycle more.
- Found a new hobby -> started learning piano. Tech used to be my hobby before it became my job. To me, a hobby is something you do for pure fun with no expectations.
- Developed a new spiritual attitude about certain life situations.
- Learned about life balance -- straight out of college up til that point I was a workaholic.
The key though to know is you will figure it out. Everyone else in this world either has been or is in the same boat as you man, so you'll be OK. You'll come out of this 6 months later with a much better and whole new perspective on life. By the way, there's nothing wrong with choosing to quit or change directions, just make sure you make it a consciously-thought-out decision so you can rest solidly on that choice years later in the future.