Yes, honestly, you are overreacting. 
It’s normal to feel anxious and out of place in a new environment, especially one different from your upbringing and far from home, where we don’t know anyone. Most of us have felt this way. Deep breaths and relax. Be patient with yourself and give yourself time - not hours or even days, but weeks and months.
Classes haven’t even started yet. Once you begin classes, things will feel more structured. Commit yourself to getting involved in activities that interest you and speak to you. Try several at least, more than you think you have time for. You can always drop ones if you don’t click with the mission of the group or the people but it is a great way to “find your people”.
Make an effort to greet people in your dorm, on the path, etc. Just be a friendly face that says hi. You’ll be amazed how much that simple gesture will enable you to connect with others.
Good luck! Chin up! Don’t give up. We’re here if you need us for a pep talk.