I just figured out something which i think is important. I think i have object permanence issues with attachment figures. I think it's how I coped as a child with my inconsistent parent. They became somehow 'not real'.
So when you didn't email back during the break I was angry because I felt like you didn't exist if you didn't reply. I also think i have been this way about my ex all these years. I convinced myself he didn't exist, so that when i went back to the flat it was heartbreaking because it was all so real again. It's making a lot of sense to me. And explains why i feel little attachment to anyone apart from the people under my roof, and you.