Princess, I am in my final year of a Youth and Community Work degree, and I still remember my interview like it was this morning! I too fall apart at interviews, and my interviewer was really intimidating (although I don't think she meant to be!)
There are NO trick questions; they will probably ask you your motivations for wanting to enter into Social Work, and what you feel you can contribute to the course. Social Work is very emotionally draining, like most care sector jobs, so it helps if you are quite a strong person.
If they ask, you could talk about coping strategies you have devised for the emotional workload involved-to me, this would show forward-thinking and commitment.
When you get an interview, ASK what it will consist of...Then you'll be better prepared. Also, confirm this with each individul Uni, but it's usually more than acceptable to take in your CV and some notes to prompt you if you get "answer freeze" like I do!
Good luck.