Did not feel good after training

Hello PingSkills!

Today I felt a bit bad after training because my skills got a bit worse and my short serves were ruined. We used to have a table in our school and we played on it. So when I came to training I were warmed up and performed well. But now they took it away and when I came back to my training, my serves were totally going wrong they were long or it was a fail like into the net. I still won alot of games but not that good as usual. My wonder is if you have any tips on short serves and what it could been. The thing is that I start to think my rubber gone out because I have had it 3 months playing like 5-15 hours week. I also feel the surface gone away. Is it time for a switch or should I train the short serve?

This can be really helpful!

Thanks again PingSkills!