As Salah said, You have successfully Projected.
Anyone can achieve Astral Projection in Seconds, if they concentrate properly.
Somehow you did it.
From my experience, I used to project in few seconds after I sleep and sometimes after few hours. It depends on how much you are concentrating and how much you are willing to.
You had the experience for only 5 secs because you may be excited which broke your projection or because you are new you were not projected for more time. Projecting to Astral Plane is pretty Easy, But staying long is the hard thing :)
Feel free to ask your questions :)
Regards,
Praveen