Firstly, there's still a chance they might accept you, have faith and don't assume the worst until results day.
I retook my A2 this year, still got 5/5 offers, 3 of which where Russel group universities, with CCD overall, ABB at AS.
If lboro don't accept you and you don't want to fall back to your insurance then retaking your A2 isn't a bad idea.
And if you do retake A2, relax! Enjoy yourself and have fun for the first months just like your friends will be doing, and plan to pick the work back up at least by Christmas. It gives you 2/3 months then to settle down or even find a part time job to make your PS stronger.