This three-wave longitudinal study (n = 1341) examined between- and within-person effects linking fear of missing out (FoMO) and social media use to psychological need satisfaction and well-being over time. As such, this study tests the premise that FoMO can be understood as a self-regulatory limbo, arising from deficits in psychological need satisfaction and/or lower well-being. This limbo is suggested to lead to reciprocal relations between these constructs, yet no study so far has formally put this to the test. At the between-person level, all variables were related. At the within-person level, part of a reciprocal trajectory for FoMO and social media use was found. FoMO at T1 predicted social media use at T2, which subsequently predicted FoMO at T3. The results provide partial evidence of a self-regulatory limbo and raise questions about current theorizing in which such a process is believed to arise from deficits in psychological need satisfaction and psychological well-being.