Comparing yourself and feeling inadequate

I train with a PT, I always want to do my best and be the best but I feel insecure about one of his other clients as she is really strong and lifts heavier than me so my thoughts are like what if she is better than me or he thinks she is better than me, then I feel bad about myself and insecure/inadequate. He has given us the same body fat target and we both reached the same results at the same time so I started to feel anxious and scared she would get it before me and that makes her better than me. My trainer asked me to gain some muscle as he thinks I lost some whilst reducing my body fat but I felt really scared and frustated as I was close to the goal he set me and I think she will get there before me now, I have the habit of overeating and I don’t want to think this way anymore and I don’t want to overeat or feel bad if she does get it before me