strangest thing happened

I am the only developer, DBA etc.. for a small project.  Today (yesterday was 
everything was perfect) many of the sequence numbers fell behind what is the 
actual PK value.   For example the invoice PK sequence current value = 1056 
but the table PK was 1071.  Nobody (other than myself) knows how to 
edit/access the postgres server.  So

1. Does anyone know how this could have happened?????? Other than human 
interaction.

2. Does anyone have a script to reset the sequences to match the tables? 

Thanks in advance,

Johnf