I am quite literally the most anti-social person in the entire world, I hate most (if not all) people, and even I graduated with three friends who I'm still in touch with two years later. Honestly, if I made friends, there's hope for everyone.
Group work is a good way to start working with people, and that's bound to happen at some point. Have a look at what societies are offered by your SU and join one that interests you. Immediate conversation starter there.
But three weeks isn't really that much, so I honestly wouldn't worry.