Over the past three months I've made a friend that I spent quite a lot of time with before he went on vacation for a month. We still chat a lot but for some reason I started to feel annoyed towards everything about him. Everything he did agitated me, and I didn't really look forward to hearing from him. A week later and I don't feel so annoyed anymore, and I'm kinda looking forward to his return. 

Granted I have been particularly moody while trying to deal with opiate withdrawal, this isn't the first time this has happened without a particular event setting it off. Has anyone experienced this before? 