I would really think twice about doing a 4-year degree in the UK if you're funding it yourself. You're going to pay twice the price for a degree you could complete in the US, and you won't have the same opportunities for financial aid (i.e. grants/scholarships) as you would in the US.
It's a different story, if, for example, you've done your 4-year degree in the States, and you decide to do a one-year program abroad, because then it's technically more cost-effective than doing a two-year Masters program back home.
I think it's great that your dream is to live and study in the UK, but doing that requires a LOT of careful planning. It took me two years to plan and save to go to Scotland to do my Masters. In the long run, you really are better off doing things properly, so that you don't get yourself into massive debt. I know that you'd probably like to be near your friend and see how things work out, but I believe that in life, roadblocks are put in our way for a reason. Roadblocks make us think about our choices before we make them, and take a better approach to things.
I would advise you to think carefully about what you want to study, find a US university that you like that offers that course, and enroll. After a couple of years, you will be able to do a semester abroad, and if you like it in the UK, perhaps upon graduation, you can do a BUNAC program and work in the UK for 6 months. This will give you the opportunity to travel, meet new friends and have new experiences.
While you may say that you're not going to Leeds FOR Michael, do you think you'd be considering going to Leeds if he wasn't there? This is an important question to ask yourself, and be honest with yourself about, because hypothetically speaking, if you go to Leeds, and you fall out with Michael and his family (never say never!), you're going to be basically homeless and have no support system there. If you already suffer from depression, just imagine how you'd feel if you had the rug pulled out from under you!
I'm not saying these things to be mean, but in my experience, life only gives us what we're capable of handling at a given point in our lives. I would've LOVED to have been able to live/study/work in Scotland back in 2000, but I simply wasn't ready for it. At 21, I don't think I was mature enough or confident enough to make a real success of living abroad. A couple of years can make a huge difference in terms of maturity and clarity regarding a situation. Sometimes we can't always have what we want for ourselves WHEN we want it, but we CAN do what's best for ourselves. And in doing that, we can ultimately achieve what we want for ourselves. If something is worth having, it's worth working towards and doing properly.