Why do I feel fully convinced of my theme 😞

My last and almost life long theme/sub-theme largely subsided recently and my ocd felt like it wasn’t even an issue. Then I went on winter break from uni and being alone made my mind come up with a whole new topic to obsess over. TLDR on my fears, my advisor wouldn’t email me back for a while about signing up for classes so my mind started to worry “what if he doesn’t in time and you can’t enroll this semester and you lose this whole life you just built and all these new friends” So when that issue was resolved my mind found other scarier ways I could be uprooted from my current life and friends that I’ve grown so attached to. Then my mind remembered back when I was struggling with false memories and scrupulosity and I essentially made a post on a forum 2 and a half years ago saying I did something or was convinced I did something that I never actually did. Now I’ve been spiraling about someone finding it reporting me and I either get seen as a horrible person or arrested or something over something I never actually did but “admitted” to out of fear of going to hell. My mind won’t let it go and keeps finding new reasons for it to be “valid” “logical” or even inevitable. I feel like it’s just hanging over my head and I can never rest easy. Especially when I try to focus on my daily tasks or plan for the future I get this horrible flair up of “why plan for the future when this could come back in that future and you get uprooted from all of it” my mind won’t rest without certainty being uprooted won’t happen but certainty doesn’t exist, at least not with ocd. This sucks and I miss being care free.

Anyone else feel that when they aren’t experiencing a theme that their ocd is almost non existent. It almost makes me feel like I’ve been faking it, and also makes me feel ridiculous for obsessing over things. I feel sorry for myself :/ I know that my themes are valid and felt very real in the moment, but after I “get over” them I just can’t believe that I was obsessing over something that either wasn’t true or didn’t apply to me. I would also like to know how to prevent themes from reoccurring. Health, religion and existential OCD themes tend to take turns throughout my life, I just didn’t know that was it ocd. Trying to break the cycle.

I often feel like i did something wrong even tho i am positive i didn’t, my boyfriend and i have been together for like 6 months and i’ve been completely loyal to him the whole time but recently i’ve been feeling the need to confess that i cheated on him even tho i didn’t and there’s absolutely no proof that i did something even close, i don’t talk to other men and if i do my boyfriend has full access to my phone and it’s usually a friend or me asking a simple question but i still feel the need to confess even tho i’ve done nothing wrong🥲 someone please help it’s so confusing