I had TKR 12 weeks ago Dr waited no manipulation

Hi my TKR was 12weeks ago, for 12 weeks I went to PT just 2 x a week. But did my exercises between days. My problem now is I didn’t pay attention to the fact that PT never changed in my workouts , I was doing same thing since the first week, I mentioned my knee is more in pain each week and she added heat before I stated to work out. I didn’t know what questions to ask so I let her do her professional as she is suppose to be and followed what she showed me , I gained more pain each week and I was dumb founded on why so I saw my Dr and he said I was a slow healer and to keep moving it .i didn’t like his answer, this was @ 8 weeks now I went back to Dr last week and he said we need to start manipulation.. isn’t this a little too late ? I feel ignored and left out in the rain as both knowledgeable people performed lousy service on me and I am lost on what to do, except now go through manipulation and hoping the best turn out, but I feel if all my workouts didn’t help how will this ..has anyone had this problem ? I do not want another surgery it was horrible experience and healing