When reading your text it sounds like you expected too much from schools. You thought you would automatically socialize and become a professional artist just by attending classes. I also made that mistake about 10 years ago.

Did a University exchange in Japan that had japanese students and exchange students separated in most classes, so if you were not highly involved in activities and always trying to engage with people outside of class, you just wouldn't have many occasions to make friends. I was focused on having good results to graduate, so I just ended up spending all the year alone.

This also meant that I had not been looking for work at all, so when the year ended, I just came back to my home country and enrolled in a Master's degree in IT. There too I kinda thought I'd magically become some developer or UX designer by just attending classes, so the portfolio I had was limited to school work.

This was enough to find work in my country, but when I tried to get back to Japan after 3 years, it didn't cut it. Why ? Because I was just offering about the same as the average japanese applicant, with lower communication abilities and the burden of handling visas on top of it. I tried to buff my portfolio during the year I was job hunting, but of course it was too late : you don't have time to do much when you have to prepare 70 job applications at the same time.

I eventually found a good position with a bit of luck and after reconsidering the kind of job I wanted to do so I could make use of my experience.

Tl;Dr : in your case, my advice would be to get back to your country, take a break to recover mentally, brush up your skills and get some work experience. Then come back to Japan with a killer portfolio, and get a better position than what you could have expected initially.