Meteor app on Digital Ocean slowing drastically

I have recently put on the same Digital Ocean VPS 2 Meteor apps I have made using MUPX, they are pretty simple. One of them is a kind of tchat (like Facebook Messenger), the other is more complex but I am the only user.

The tchat app has like 12 users simultaneously, tchating, sending messages, etc.

I have a 2Go RAM droplet on Digital Ocean, and when a user sends a message on the tchat (through a method), sending and receiving confirmation from server takes about 1 second. Is it normal ? Did I do something obviously wrong that I am not aware of ?

Thank you for your help :slight_smile: