My(24m) gf(20f) shows no involvement during sex

Me and my gf of 2yrs are in a long distance relationship for past 8 months. We started having sex in the same time period whenever i visited her. Both of us love each other and are very much attracted to each other. But whenever we're having sex she just becomes a 'robot'. She does not show any initiation or involvement which recently started annoying me. Its not like shes not interested or has low libido or anything but she just follows my instructions and do what i say. I do everything to her for pleasuring and she enjoys it a lot but does not do anything for me. At first i didn't take it seriously as i know shes a shy one but recently its irritating me a lot so much that sex to me feel like a job to satisfy her. I told her openly about this issue but still im not seeing much improvement. I love her a lot and would like to you give me some advice to bring her out of this bubble.