Do you have a problem with seperation anxiety? If so, how do you deal with it?

I know to other (slightly saner) people it is irrational but I really struggle when I have to (temporarily) be parted from certain people. I become overwelmed with fear that I will never see them again and I imagine every possible reason that they may not return. My loved ones are aware of this but they don’t know how bad it is, I think they see it more as a quirk of mine rather than a genuine problem but it eats me up and I am tearful and scared all the time. Any advice or reassurance that I’m not alone would be much appreciated.