mads - i was a similar weight to you last year, and i think what motivated me in the first instance was having a potential dvt in my leg - which my GP said was as a direct result of my weight. I remember sitting in the hospital ward being so scared that my kids were going to lose me.
Once that got sorted (wasnt a dvt) i went back to my gp, and i agree visiting yours should be your first step. After a long talk, he agreed to try me with orlistat (like alli but stronger). I always thought that when i got too big, i would ask for a gastric band which would solve everything, but then found out that i wouldnt get funding. SO, i had to do it the hard way.
It has took nearly a year, i started last july at 19st 1, and am now 14st 8, so have still got some way to go. But, i also agree that motivation is the key. I found the lovely ladies on shiney's thread (general health) and they have kept me going when i was wavering, as well as cheering me on when i lost weight. It doesnt have to be our thread, but i would think that some kind of motivation would be really helpful. I have major self esteem issues, and at times it has been really hard, but i think back to sitting in the hospital last year, and am determined not to get back there.
exercise is also the key - but when i started, there was no way i was going to the gym, so i basically started with a 30 min walk each day, gradually increasing the speed. I can now go swimming, with only a few little anxieties.
I wont say anything about the alcohol, as i see others have that covered
Good luck hun, and keep posting, as it helps to write things down to see things clearly
I hope all that made sense, as i am trying to finish an essay - which unfortunately isnt making much sense