Lean into this (as you may be projecting these beliefs onto your twin):
What are you missing out on? Can any of those things be fulfilled by you?
ie. fear of missing out often stems from feeling left out of something. we also sometimes are envious of other's lives when we don't feel fulfilled in our own. and sometimes we are also in fear of time running out.
What to do with it now?
Acknowledge it, release any ownership over that belief and establish your own beliefs about unconditional love. Being aware of where this pattern came from will help you to establish that you most likely took on someone else's version of the truth.
You were and are now worthy of the most beautiful love, as you are in this moment.
What can you change about your life to make you feel better about it and you? How can you shift channeling your energy from lack and wanted to creating and having?
Can you trust that anything that is meant for you is already yours? That you cannot control time, but you can control what you do with your time.