I can't tell you what your chances are based on this answer, without context. Did you get rejected pre-interview, or did you get to final round for both and narrowly missed the offers? These are completely different scenarios.
What I can say, though, is that in London (extremely competive market) I have heard of every possible combination of people getting 1 or 2 offers from the 3 MBB - e.g. BCG and Bain, Mckinsey and Bain, Mckinsey and BCG, etc.
So just because you didn't get BCG and Bain doesn't mean you will not get McKinsey.