IMO - the first thing you should do is take a week off. Don't think about it, don't work on it, don't buy anything for it. Better yet, go on a week long vacation. Go camping. Go fishing. Ride a mountain bike. Paddle a kayak. Do what ever it is you like doing (as long as it doesn't involve the van).
You seriously need to clear your head - you won't be able to truly weigh the costs & benefits until your judgment is no longer clouded by all the crap currently going through your mind.
Once you've done that, you need to contemplate why you're building the van *today* (the answer may be different than when you started building it - and that's OK). My guess is that you'll come up with one of three answers:
1: You're building it to fit a lifestyle that you either currently have or are actively trying to achieve.
2: You're building it because you like building it.
3: You're building it because you started it & feel that you need to finish it to justify the time/money you have already invested in it, even though it doesn't really fit your lifestyle.
If the answer was #1 - keep the end goal in mind. That's probably motivation enough. If it's a long project - get it mobile & usable in a limited capacity so you can use it *now*. Even if it isn't finished (IE: sparse interior, no running water, no heater, etc), at least you can use it on a limited basis. It won't be nearly as nice, or as comfortable, or as "easy", but at least you're getting out there and enjoying it a bit along the way.
If the answer was #2 - then accept your hobby for what it is. Building it *is* the journey - so there's no need to get frustrated by slow progress. Who cares if you take a year off - or two years? Why rush to the end if the end isn't what you're chasing?
If the answer was #3 - get out now. Do the least amount necessary to make it marketable, sell it (likely at a loss), walk away. You will bring no happiness to your life by continuing on your current path - even if you finish it. Trust me - if this is where you are at, then this will be a difficult conclusion to come to, and even more difficult to deal with. But once you do - you'll free up mental & financial resources, & a lot of time, for things that are a better fit with your life, and will ultimately be much happier.