I think you know the answer and don’t realize it. Your manager is sending you all kinds of signals. Your bonus was ‘mediocre’, your review was ‘vanilla’ do these sound like what a manager would do if they liked the work being done by their direct report? No. The real key was how evasive your manager was when you asked about a promotion. To me, this means they do not have the confidence in you that should be there. If your company is struggling or has cutbacks, then you may be vulnerable. I suggest you evaluate what you want from your job and career and look at other opportunities. The sooner you do this, the better. Good luck.