What a powerful experience! I totally understand how you can leave your body & travel around. You are right to be careful because there are other entities that don't have good intentions who look for bodies left by people doing astral travel. This is actually a yogic siddhi, but nothing you'll learn in an American yoga class! But traditionally, it's just part of a greater path to spiritual awakening & realizing we're far more than just bodies.

I also wrote about my encounters with spirits who left, but thankfully they were people I knew & less scary. I make conscious efforts to block out anything with impure intentions...
you can read it here: Life After Death