Is it normally for me to be very upset my brother is moving out?

I’m 18 and he’s 20 so he’s been dating this girl for about a month and wants to move out of state with her. But we’ve always been really close, he’s supposedly moving out come the summer but his relationship don’t tend to last very long. I’ve been spending the duration of my time just prepping myself but that’s led to long periods of crying and waking up in the middle of the night
Is it normally for me to be very upset my brother is moving out?
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