I would recommend retaking the year. See if your current college will allow you to do that. If not, perhaps go to a different college?
Most universities/courses won't be to bothered if you retake the year, unless you apply to, like, Oxbridge or somewhere. I retook year 12 due to illness during the year and therefore not doing as well as I should have and still got into a Russell Group uni
Resitting the AS exams alongside your A2s would also be an option but that would require a
LOT of hard work and would be difficult as there is a jump in the workload between AS and A2. And especially now there aren't any January exams to spread the load across the year might also make it a little bit more difficult. Resitting is also easier as you've already covered the material and it's basically like a whole year of revision. I also found it made A2 (for me at least) that much easier because it meant I had a really good understanding of the easier stuff at AS.
Hope this helped!