Hello, Rolly! Welcome to the forum! I'm glad You came here and i hope we can help You become Yourself again.
We all go down the rollercoaster once in a while; the only difference is how sudden and steep the downhill is. To loose such a good friend that You called her "soulmate" seems like quite a fall. The problem with having such good friends is, which You already know since You're currently experiencing it, that the higher we climb, the harder we fall. One of the major points of getting back in the cart and go uphill again is to realise that You can reach the good times You had with her once more, just like Vivid describes.
To do this some people, like myself, change their ways about life a little (or alot); i tried to forget about the past completely and thereby erase it from the rolloercoaster and start a new life which goes uphill right from the start. Everytime something truly negative happens in my life i try to overcome it by forcing it out of my life by creating a new life. Seems a little dramatic, perhaps, but i am the living proof that it works very well, if You succeed.
The other, more classic way to do it, can only be performed alone by the really strong one's; to simply keep on with their lives and slowly try to recover from the greif by letting time heal the wounds for them. If this doesn't work some people might start looking for professional help or tend to easily accassible places, like this place, to try and talk it over there. If the classic way doesn't work You'll probably end up in a full-blown depression (which simply means You've been sad for too long) and You'll start to wonder how life ever can be good again. This is the situation that most people here are between at the moment.
This is the problem we have to face and we must get to understand that,
if the current life we are living isn't joyful enough for us to recover from that negative thing that happened in the past, we have to fill that part up with something else. This is what the vast majority of people in depression need help with understanding, and sometimes finding.
It can be anything from parachuting to inventing a new soup recipe and most of the times it's something You never thought of before, maybe even something You didn't knew existed. Every person who feel something is missing in their lives have some kind of goal they must find and reach to be able to be happy in life. Everyone has their own meaning of life and we all should struggle to reach our dreams because we were meant to reach them.
I, like Vivid, am also open-minded and willing to talk to You further about anything You'd like. Don't hesitate to send messages in private either, i am only here to help.