Hey I'm about to go into my second year of studying at KCL and honestly I was TERRIFIED of it, I was worried about being lost, about moving around in London and about the people there. But throughout my first year I haven't had a single bad experience. My main worry was the social aspect of it as I can get pretty awkward and find it hard to make friends. But, I found that joining societies has been a great way to meet people and make new friends so you should probably give that a go. In terms of sixth form, I personally hated mine and starting uni has been a great relief and I haven't looked back since, in terms of both friendships and especially the study. A levels have DRAINED me and uni work has so far been much more relaxed and easier to handle. But overall I would say the way you are feeling is completely normal and there are different people at KCL you can speak to about your feelings and they may be a bit more useful at finding solutions. Their student services team in particular has helped me with settling in in London