Someone said something to me a few weeks ago, it really hurt my feelings. They never apologized for this particular thing, but apologized in general, for being selfish and inconsiderate, and promised to try to have more consideration for my feelings in the future. 

They really have been better, things should be great now.

Things aren't great though. I cant stop fixating on what they said. I keep playing it over in my head, obsessing about it. I cant sleep, I cant concentrate at work.

All of the good things, and the positive steps forward we are making are drowned out. All I can see is bad.

We are supposed to have moved past this, but I cant. Its making me hate them more and more everyday. What they said triggered a painful childhood memory. I feel like that is what I'm upset about, but my brain is convincing me this person is the cause of all the pain. 

I want to make him understand how much he hurt me, but if I talk to him about it, I will sound crazy, I know I will. I know I'm being crazy, but I cant make it stop. Another part of me just wants to punish him for it, to make him hurt, so he can know how it feels. He doesn't deserve that though, this is my bull crap, not his, he doesn't deserve to have me take this out on him.

How do I pull myself out of this? How do I detach this current situation from the pain of my childhood issue? How do I stop myself from blowing up?