I lost someone recently
This really hit me hard. I can feel the pain, and reading it seems like you are used to losing people (not saying it in a negative sense). I mean that now you better know how to deal with the discomfort or stress which comes after someone leaves you.
But still my heartfelt best wishes are for you mate. I don't know the personal reasons why they left that is why I can only say this.
As far as I am concerned, I have lost someone but that was the only someone I was having a really close relation with. Still we spend some time together, often we are together, but lost them.
Losing people is inevitable, you'll find out soon enough if you haven't already. It's not always a nice feeling, depending on the relationship, but we have to deal with it, carry on, hold that person in our memory or discard them as appropriate.