I joined from the start of the year after my interruption and was with the year below, or the cohort progressing onto that stage. Generally, people don’t care and one or*** about two were curious enough to ask why they haven’t seen me around before.
Mostly in groups you are allocated one so you don’t have to choose and if you did you can email professors to see if anyone else is in the same boat and you can be paired with them.
I would say try to monitor your mental health the best you can and have support throughout since you are vulnerable to it. Also only disclose it to your colleagues if you feel comfortable. Otherwise just offer simple answer if they get curious and try to connect through general conversations.
I think for me it helped to understand I was there for myself and my future, and many are too. Try to progress, engage in societies, learn skills and apply for placement or internship if that’s an option. You will set yourself better for the future.