My plugins keep resetting everyday I don't know why, is there a fix?

[NoPulp]

I made a server and I had skripts, shopkeepers, worldguarded areas but everyday when I wake up the server plugins are reset and I'm so confused and mad, If there is a fix pls help me

[NoPulp]

This is what it said in console 

[21:21:21 WARN]: **** SERVER IS RUNNING IN OFFLINE/INSECURE MODE!

[21:21:21 WARN]: The server will make no attempt to authenticate usernames. Beware.

[21:21:21 WARN]: Whilst this makes it possible to use BungeeCord, unless access to your server is properly restricted, it also opens up the ability for hackers to connect with any username they choose.

[21:21:21 WARN]: Please see http://www.spigotmc.org/wiki/firewall-guide/ for further information.

[21:21:21 WARN]: To change this, set "online-mode" to "true" in the server.properties file.