Oh Sassy, it sounds so hard for you. I don't think you're going insane, it may feel like it, and it may even be a grateful release, but i do think it's normal.
In the first few weeks/months after Ciarans death i used to think about the seconds, the minutes, the hours. My goal would be to get through each hour, and suddenly a few of them would have gone by, bringing me closer to bedtime when, if i could actually sleep, it would mean that i had survived another day.
I so wish that i could make things better for you, that i could take away the hurt. I don't know, sometimes i was grateful that i hurt, bcause it meant that i could still feel, especially when i was in the stage of thinking that nothing could ever hurt me again as the worst possible hurt i could imagine had already happened.
I've come to the conclusion that grief and pain are the price we humans pay for the love and total commitment we have for another person. The more we love, the greater the pain. But, would we have it any other way?