Oh don't worry, just enjoy your life x Why should you care about what others think, matter of fact, you don't need to explain yourself to anyone nor tell anyone your in 2nd year, Freshers week is for everyone to get along. So don't worry about that x
In terms of anxiety you should speak to your GP about it and see what they can do for you. You can just introduce yourself and leave it as that no need to explain yourself to nobody. Enjoy your life, remember we only have one life to live!!