Is this for Law and a language? It won’t be easy to go back, but if you don’t all the effort thus far will be wasted, and you will feel pretty grim about yourself, for a long time. There basically isn’t an easy or happy option here, so you should take the better of the two evils and go back.
But make sure you ask for support all along the line. Your staff should be eager to provide it. By selecting you they have committed to getting you through the course. So work with them and just get your head down and grind your way through.
I teach at a RG university and feel very strongly that once we have admitted a student, our role is to get that student through the course. I am far from alone in this, and you will certainly have access to a tutor who will see things this way too.
Also, there are so many welfare structures in Oxford, so lean on them.
You are quite capable of passing the course. It’ll be a big volume of work, but the requirements are very doable in terms of level. That’s just how the system works: you deal with complex concepts but are expected to produce work at a considerably lower conceptual level. You just have to plough through it.
If the language is the problem, can you drop it? You can still put it on your CV as 2 years post A Level. This is how it would work at my university.
You have made it this far. One big last push and you are through.