BBB at first sit limits the med schools you can apply to
Aston
Bristol
Exeter
Sheffield
Southampton
Kings
Edge Hill
Newcastle
Of those Aston and Kings need A*AA anyway and EXETER needs A*A*A* predicted to have a reasonable chance. Newcastle would need the same, as thye require an A* in any resat subject.
Sheffield, Bristol and Southampton need high UCATs.
So I guess it depends a bit what you think you can achieve in resits and UCAT.
If you think you can get a really high UCAT, resit and reapply. If not, it may be one of the few occasions where GEM may be the better option, but choose a course that leads to a career you would be happy with long term, as GEM is even more competitive.
But also check out if you meet any WP flags, as these can lower requirements considerably.