I had the very same experience two years back !! but back then i was already into Opeth soooo much, and Bleak was one of the songs that spoke to me in a personal level. But Opeth never been the symbol of Hate to me by no means. I would pick up Bloodbath songs instead ah yeah.. Hate seems the only way sometimes, one of the things that helped me was slayer : Hate heals you should try it sometimes (even tho i'm not a slayer fan).It must have been about 3 years ago when I was going through a hard break up and I was a total mess, I couldn't get my self together, I couldn't think straight. It was like my life had ended and I had been swalloed up by the dark abyss. Somewhere along the way, I lost my self in all the tears I shed, all the idiotic mellow love songs that are full of emotions, and all the pain off the loss, nothing and noone could make it go away and I had to bare it alone cause noone understood me..
One day I randomly stumbled upon Blackwater Park and Bleak (I don't remember how though). My sadness became hate while I brain washed my self clear from all of my stupid love emotions I had still lingering in me and I got over him soon enough. In those songs I found the relief I seeked all that time. I grew to love Opeth and hate that person.
After I found more of "The Opeth Drug" I sat and cleared my mind and heart from everything I felt. Hate, hate, hate and more hate to come. Eventually I found my peace of mind in the next months that followed.
I may not face relationships the same way, even now, but at least that made me stronger. Opeth for ever.
Anger and Hate > Love