You know, a lot of things changed. What never changed is the illusion to keep playing tennis, the illusion to keep doing well the things, and the illusion to be in a good position of the ranking and...
It's more a tennis problem than a mental problem. The transition is difficult. It depends how much time you have. Playing on grass can sometimes be a bit of a lottery.
In tennis, because of the way it's scored, I don't think that scoring one point out of luck is ever decisive in winning. But, of course, it depends on the moment.