FOMO is a feeling somebody else is making money off. Notice who.

Feeling that you are missing something is manufactured deliberately, because a person who feels behind buys, scrolls and refreshes. It is not a fact about your life, it is a product with a business attached to it. Seeing the mechanism does not dissolve the feeling, and it does reduce its authority.

Next time it hits, ask what you were doing right before it started and who benefits from you feeling this way. Then go back and finish what you were doing. The feeling passes considerably faster once it has been named.