Travel can be a life changing experience - I caught the startup bug when I was travelling. I definitely felt down about being back in Melbourne for a while, it took about a year until I started to appreciate things about it again. I've been helping to build up the startup community here too so that helped.
Sounds like you're going through a significant change in yourself and view of the world. From the info you've shared, I'd pick door number 4, remember you need money to eat, but take opportunities that come your way. But be prepared to be disappointed whatever you do, unless you run your own business you will always be working to someone else agenda/goal and you may still end up working on 'waste of time' work, whatever the field.
There'd be something wrong with you if you weren't on a downer right now but at least you have the skills to hit the ground running so to speak.
When I got back it was Winter in the UK and we lived in out friends attic (not perfect).
After trying out being a postie for a week I realised I needed to return to design and had to teach myself to go from zero to hero on a Mac.
I got a job that I hated but I learned enough to get me on track again.
Going back to working in-house can be a bit of a shock, especially after being your own boss but at least you'll be able to eat and having money opens up your options. (Like TREX said).