I agree it's either the mod or the batteries. If you have other batteries, try them. If not, perhaps travel to a vape shop near you if they have decent employees, they might be able to help you isolate the problem. If it's under warranty, do that sooner rather than later so you can warranty your mod if need be. It sounded like a brand new setup, is it? Or is this something that just started happening? It could be user error, I wouldn't rule that out at this point, but could equally be something else.
Good luck!
Anna