Skateboarding question?

hey can you help me? usually i can ollie like a 4 set or 5 but now like i was skating and i could only ollie a 3 set and when i tried a four i didnt pop an ollie or i kicked the board away. and when i tried boardsliding this ledge off a five set i fell on my @ss so why am i getting so scared of small stairs and stuff suddenly, last time i skated i could do this all fine. Thanks in advance