OCD Action

I just don't know what to do anymore, I'v had CBT back in high school and all it did was make things worse and it's not going away, and I don't think it ever will.

According to the psychiatrist that saw me in hospital I had attachment issues after I lost my nan, but after that event it all took off.
I was let out after that and my parents were simply informed to keep an eye on me and that he thought I was in no immediate need of help, then I met my current partner a few weeks after and we got along really well, and after the first night I ever spent with her I couldn't stop thinking about her, I gave up my friends and everything and my world immediately revolved around her, and ended up getting engaged.
And that's when I saw everything happening again, as weeks went on it hurt even more to be away from her as though there was a burning hole in my chest, wondering what was happening to her throughout the day and this would escalate to the point of seeing horrible images in my head that just wouldn't go away.
She was always a public sort of person and wanted to go to a party, I begged her not to but she did anyway, and the images drove me mad that night, into having what my old psychiatric nurse described as an "out of body experience?", and did horrible things.

Because of my interest in computer security I saw the option of spying to make the images and burning go away and ended up infecting most of her equipment and regularly stealing logs and such in a search to make it all go away until I started seeing bad things in the logs where she had been flirting and such.
After this I couldn't trust anyone and I couldn't help but spy on her 24/7 because she meant the world to me.
Repeatedly she would say that she would never do it again and in my nature I couldn't help but give into her and think everything was going to get better but it didn't.
That's when I got referred by the nurse to a psychiatric nurse who started CBT with me immediately after I described the way I was feeling and my past to the nurse, and deciding I had OCD and generalized anxiety disorder, and he got the doctor in who said I couldn't have pills.
I was really guillible and would do anything she said and believe her every word back when I was in high school, and she convinced me some people were out to hurt her and steal her from me to the point where she made marks to make it look like they did, and I started getting symptoms that they said was hypersensitivity?, around everywhere we went, watching everyone assessing everything they did, checking where they were looking and why, plotting every single aspect planning for the worst to make sure that if something bad happened that I was ready for it and it drove me down to rock bottom, and I ended up carrying a weapon and nearly hurting someone, and it's against my nature to hurt people, and that's when I stopped seeing the psychiatric nurse as I lied to him telling him I was all better.

After I got evidence to prove she was lying she confessed and we got back together again, and I couldn't stop the images, they just kept burning in my mind over and over again and I became really bitter and horrible towards everyone especially her, and ended up cheating on her out of spite and anger. I'v regretted it every day since and still to this day it keeps coming back up in my head, all the images of her being unfaithful, other people moving in on her and me hurting people(<most distressing of all because I'm harmless). I'm finding it really hard to resist spying on her and I love her more than anything and can't bare the thought of losing her.

But now she wants to go to a festival for a few days, and I can't take it, if she so much as mentions it I break down and the images won't leave me alone and I end up nearly having a panic attack.

I just don't know what to do, it's either I go there and ruin it for her by getting overprotective and scared, or I don't go and suffer.
I'm scared to see my GP because I don't want them to stop me seeing her or do more treatment that doesn't work.

Surely there's someone who's felt the same? :/