I think many of us have had experiences like yours, try not to beat yourself up too much.
My masters supervisor told me my work "was nothing special" and my postdoc supervisor basically called me fat. Academia has such a rigid hierarchy with vast authority differences that it, more so than many institutions in the modern world, allows people to behave quite badly and to mistreat subordinates. Most academic departments do far more to protect staff than graduate students or postdocs.
More than anything, you want to keep producing work. It sounds like you've stalled a bit in your current environment, which is a shame, but even if collaborations are tough, you should keep producing on your own to help you with other fellowship applications and future positions.
It's strange that no one wants to collaborate with you or sponsor you. Unfortunately, if you're able to, I'd suggest some serious soul searching here. It seems quite unlikely that as a whole the faculty have plotted to be mean to you. Rather, something has happened that makes them not want to work with you. Think about a guy who hates every woman he's ever dated - HE is the common element in those relationships.
It's a bummer the tenure track position fell through, but if you got that offer than you can get other offers.
For more pragmatic ideas: can you try to get a sponsor at a different school? could you apply for a tenure-track position at a lower ranked school (and plan to spend 3 years improving you research and grants to apply to a better school later one)? can you keep working there without a fellowship?
You mention leaving academia, but not wanting to "return home". This is a bit of a drastic step, but I think most junior academics under-estimate their employability. You say you're not sure what you'd do if you left academia, but that's something you could spend some time thinking about...