I feel like when we wake up after a dream, there is a subconscious mechanism that kicks in afterwards that tells us “that was not a dream, not a real memory, so dont worry about it”, and this recategorisation of the memory washes away a lot of the emotions tied to it. Thats why you can have outlandish dreams about flying or going invisible, but then when you wake up you don’t literally think these events actually happened.
Its the malfunction of this mechanism that causes issues, with both OCD and regular dreams. Im sure you have had experiences with dreams that you woke up from and were convinced, at least for a short period, were real. I know i certainly have. Im sure its probably the explanation behind 90% of all alien abduction and ghost stories – dreams that ended up being categorised as memories.
More to the point, when we have particularly horrible OCD dreams, this mechanism can hurt us in both cases. For example, if the mechanism doesn’t kick in, we can become convinced that some horrible happened or that we want to do something horrible. However, when the mechanism does kick in, we can get this discontinuity between the objectively horrific content of the dream and the seeming lack of emotional response upon waking up. That sounds like what might have happened in your case – you had a dream with objectively bad content but woke up not feeling that bad about it, and that discontinuity is what is distressing because it makes you feel like you don’t mind that bad content that much.
So perhaps consider that going forward. When you have a bad dream but don’t feel that bad about it when you wake up, thats the correct response, because its a dream and its not real. You can thank a million years of human evolution for your subconscious ability to tell the difference between reality and dreams, even when your conscious mind is being throttled by fear.