If I use the Lightning Network, will I double spend?
Have you understood how the lightning network works? In a nutshell, it is a second layer consisted of nodes which maintain payment channels with funds deposited in multi-sig addresses from participants. Read the basics here:
Basics of the Lightning Network.
What do you recommend?
I recommend you to start using it. Then, once you're get used to it, try convincing others use it too. By spreading it, merchants will sooner or later adopt it.