Why is existential ocd so freaking difficult compared to other themes?

so I need to get back into ERP, but it’s so hard to manage these thoughts and learn to deal with them. like I swear my mind has to make everything about it. Like every time I clean my room, my mind’s like yup make sure it’s clean so when your parents find you, or something so stupid like if I get a headache, my mind convinces me that I like the pain and that that’s why I get my thoughts because I actually want to do it. It’s so exhausting. Because I know I would never want to take my life and I treasure my life so why does it do it to me? It’s hard to comprehend the fact of these thoughts too because I don’t know many people with this exact theme. It’s such a scary feeling. And I’m constantly questioning whether I have actual depression or if it’s just my OCD. Yes I have been diagnosed with suicidal OCD, but my mind still tries to convince me otherwise. I just don’t know how to let these just sit and pass without panicking.

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.

So with my theme of ocd, ( hocd ) I get persistent intrusive images, and thoughts. It’s not like one or two a day. Like if I’m out for the whole day they’re constant. I feel I can’t even look at a girl now without her intrusive thoughts about her or about me fancying her and even sexual intrusive thoughts.. It’s awful. It’s everywhere I look. Is this common with ocd with any themes? Like is it constant for you guys too?