I also struggle with this. I have had been diagnosed with OCD for 7 years now. So I tend to get confused to since I have been living with this for so long. I would say that if you get a thought and you can distinguish which one it is (normal or OCD). Take a second to think if it’s intrusive or not. Intrusive meaning any unwanted thoughts. If you think something and get “weirded out” or “uncomfortable” it’s more than likely intrusive. But if you think something and it’s just neutral. Then it’s your actual feelings. OCD doesn’t define you as a person. It doesn’t make you “not normal”.