A quick update, thought I'd post here rather than resurrect my 'avoiding splitting' thread.

The person I was worried about has been off sick. I've been feeling really empty and low all week. But that's better than what I was fearing which was intense anxiety.

I've had a good chance to reflect on how I feel about them and am now just trying to step back emotionally from the whole situation. Things would be so much easier if I had more casual friends at work, then I wouldn't develop such extreme hopes and fears over individual people.

Work is a depressing place to be right now but I'm hoping things will improve in the future. I just wish I didn't get so emotional about everything. That would be a good start.