Hi there
Sorry to hear about your situation. I know it can be difficult to make friends in University, I also struggled with the same issue in first year, and I know many others who are in the same position too.
Whilst your flatmates are in different years to you, feel free to talk to them. Many students know how daunting it is to feel alone at University. There is no rules that you can only hang around people in first year.
It is true that most people in seminar groups leave right after lessons, perhaps you could move seats around the classroom during different lessons, so you can perhaps have a chance to work with them in group discussions? I find it helps to start a conversation afterwards.
I do agree with the points about socieites. Perhaps the ones which you have joined are more academic based? I know that they do not host many events. Try going to ones that are more popular (e.g. they have an active social media page that displays their events). This can be quite helpful in making friends.
Perhaps also check out what your student union/ support and wellbeing team offer: there may be buddy schemes where you get paired with another student
. My university offers things like buddies for walking and coffee. Perhaps your University has something similar?
It can be tough trying to find friends at University, and if you ever need it, speak to your University's wellbeing team, I am sure they will be able to help you out (as they also host their own events!)
I hope this helps.
Chloe
University of Kent Student Rep