Applicants who resat their A-levels, how did you sort out predicted grades?

So I'm trying to get over the shock of this morning after results day (got BBB when i was not expecting it at all) and I am now currently trying to bounce back.

My plan is to sit the ucat again, send off another UCAS application for med, and redo my a levels during the summer. However, that means I will need another reference and predicted grades.

If I ask my sixth form, even if they agree to be my reference, there is no way I will get predicted any grades which are any good enough to apply with due to the results I have attained right now.

That leaves the option of going with a private centre, however I have my ucat booked for the 24th September, and of course for med you need to apply before the 15th October, and likely I will need to complete some sort of mocks as evidence for the predicted grades I will be set... however there is no possible way I'm going to get have enough time to prepare enough for these mocks to score high enough to be predicted A/A* in between a three week gap.

So in this situation what do I even do? Maybe I'm misunderstanding some parts but let me know about your experiences