I am very sorry you are having such a tough time as an international student. What should be an enriching and exciting time has become a nightmare for you. It makes sense to me that you miss your family and don’t want to try to make friends anymore.
It’s important to hold onto the fact that you make friends easily at home and that you are successful there. The problem seems to be in your current situation, not in any personal inadequacy. You may not have been adequately prepared for the differences in the two countries. The very things that made you successful academically and socially at home may not work as well in France.
Your anxiety has become so intense that you aren’t able to think clearly. Please take a deep breath and try a couple of things before you give up and go home. It would be a shame for you not to get the many benefits that come from exploring a different country.
First, get some help. You need someone to talk to who understands the cultural differences you are experiencing and who can give you some guidance about both social and academic expectations in France. I hope there is a guidance office at your school or a liaison for international students. If so, make an appointment immediately. If not, identify a teacher or administrator you can trust and ask for some help.
Also, talk to your teachers about your experiences with group work. It may be that how assignments are done in France is different from what is expected at home. The teachers need to know that any mistakes you have made are a result of not understanding those differences. They can help you understand how to do work “properly” in you current school.
In addition, I hope you will find an activity you can share with your peers. Doing things together is a great way to gradually make friends. Look into participating in a sport your love or some other activity that you do well in. Let people get to know you separate from academics.
It makes sense to me that you are turning to religion to help you. People can take great comfort from their faith. Just don’t let it isolate you further. Instead, see the leader of your spiritual community as another resource for emotional support and practical help.
If nothing makes the situation getter, there is no shame in going home. The program you are in may not be a good fit for you. You may not have been adequately prepared for cross-cultural differences. You may need to develop some more skills before venturing into such a challenging situation.
The important thing is to learn what you can from the experience and to work on whatever personal goals will make the next time more successful. And yes, you do need to ready yourself for a “next time”. The world is becoming more and more global. It’s important to your self-esteem and to your future for you to make international travel and work a successful experience for you.
I wish you well,