Hi Sunflower
You're most definitely not alone. I'm from the UK and have the same problems. For the last few months I've been going 2-4 weeks dry and then doing something stupid, like thinking I can have a pint or 2 to relax. I end up binging as I, like yourself, simply can't stop when I start.
I also live alone and it's those times when I'm home alone and restless I find it the hardest. There's such a massive drinking culture in the UK; it can feel very isolating to try and remove yourself from it. Don't give up giving up; it's hard to completely change that mindset but when you can't stop simply never starting is the best solution.
Don't fret over relapses but do try and learn from them. If you can use each relapse to help understand your triggers and find ways to deal with these; they can be a useful learning experience.