I finally got into Uni but..?

This year i applied to do illustration at 5 uni's but got rejected by them all. Obviously this was really horrible, and I didn't cope well at all. Anyway after months of worrying, I used ucas extra and finally got a place at uni...but something about it doesn't feel right. I applied for graphic design, but apparently my personal statement suggested I should be doing advertising design and so they invited me for an interview for that course instead. I don't want to do advertising, but thought well maybe they'll agree and put me on the graphic design course. When I arrived they had no idea I was going for an interview, and no idea that i had been recommended for the advertising course. I told the interviewer honestly that I actually wanted to do graphic design. They looked at my work, and offered me a place there and then, saying I can change to graphics in september if I really want to, but they want me to do advertising. I was so happy, but now it's been over a day since I was there, they haven't updated my track or sent me and email or anything, and if I have an offer I need to apply for accommodation next year. I'm starting to really think about it, I cant help but be critical of the universities organisation and I dunno...I just have this gut feeling that somethings not right.I have no idea what to do. Everyone is so happy for me and automatically assumed i'd go, but now i'm starting to think about using ucas extra again. Does anyone have any advice?