Is it normal i feel so abandoned over this?

Due to social anxiety and a circle of self destructive depression I've lost contact with all my friends except one, my best friend for 8 years back since high school, we know everything about each other and we're really close, we hang out a few times a week and I usually stay round his one night a week playing Xbox and watching films,

He hates the place he lives though, its a rough area, rough apartment, the place makes him feel horrible, and it makes him smoke even more weed, when he's out if the place he feels fine but as soon as he's back n that area and back in that flat he feels on edge and restless, so when he told me he's moving to London where he has relatives I should have been happy for him, he gets to move out of that place

All I could think of was how it feels like I'm loosing my best friend, I don't drive, so that's not an option, even if it was I can't exactly drive to London and back once a week like i could just walk to his before, I'm broke so I can't afford transport there once a week either because that'd be 40 pounds on the train a week or a 3 hour bus ride, 6 hour both ways or a 8 odd hour walk

Not only will we not be able to hang multiple times a week I don't see it happening much at all, its a long way away, I don't do much, I don't go out, he's the only person who actually knows me, more so than my family, I know I should be happy for him and I shouldn't be thinking of just myself and a part of me is of course happy for him but since he's told me I've just felt really, really down at the idea of loosing my best and only friend, iin? And has anyone else had something like this? How did you manage and how did things turn out?