Is this OCD or paranoia?

I have OCD but sometimes I feel like some of my symptoms can be classified as paranoid personality disorder.

1) I am ashamed to admit this but I get triggered easily by murder mystery shows. So I watched NCIS and there was case where a husband kills his wife. I was convinced that my Dad was going to harm my mom. I got terrible images of him doing something to her. He drives her to work and when he came back I would go back and check the car and the garage. I would check her seat to see if it showed any signs of struggle. This is really shameful for me to admit but I couldn't stop thinking it.

2) I am convinced there is something wrong with me apart from OCD. I spend ages on the net searching for mental illnesses and doing quizzes to see what is wrong with me. It takes a considerable amount of my time. Its like a fear of diseases but physical replaced with mental.

3)I have never been in a relationship but recently my parents had a fight. That seemed to trigger some sort of relationship related fear in me. I am not even in a relationship yet I feel anxious and terrified at the thought of one. I have dreams of having a future husband/boyfriend cheat on me or hit me or me being a cheater on them. I just spent the last 2 days making a birth chart and calculating the risks of me having a future relationship and how badly it can turn out etc. It sounds ridiculous I know but I feel so anxious. Its really debilitating and strong and I don't know if OCD can be this strong? Even the sight of a couple makes me feel cynical and weird.

4) Number 3 also makes me feel like I am gay. I constantly ask myself if I would be better of with a girl? A girl won't be able to hurt me right? I have started to feel weird around this girl I know. I get this fluttering feeling around her.I never felt it before but now I do. I have some very intimate thoughts about her. I constantly ask myself if I am gay? I also took a gay test which said I am heterosexual that calmed me. But I still feel like I might be gay? It makes me anxious around other girls.

I am so confused. I thought people with OCD know that there thoughts are irrational but I am not sure if they are irrational? What if I am right about everything I feel? Somebody help.