I can understand your frustrations, having looked at the games it looks like the same players are failing to perform in the games you don't win eg Aslan, Spencer and your sub keeper also struggles in some of them. As the previous comment says I would look at your tactics and try to change it, also I would get rid of the consistently poor performers as although they may have high ratings that doesn't guarantee that they will play well.

I am currently suffering from a lack of confidence in some players which is why I am looking into clearing out the under performers which will allow me to improve my squad for next season plus I hope I will also get an easier cup draw.