Everyone feels worried from time to time, that is a normal. Feeling worried can describe lots of different feelings from being tired or upset, shaky, frustrated or a bit sick.
There might be something in particular that is worrying you, like a test or a visit to the dentist, or you might not know why you feel worried and that is normal.
When we feel worried we sometimes start to lack confidence and may feel that we are not good enough. This is normal too.