I recall replying to your introductory post. You know... we here on PC cannot offer mental health diagnoses. Plus I'm not a mental health professional. So I can't tell you if what you are experiencing would be considered HOCD. That is something I believe you would have to determine with the help of a mental health professional. I know you wrote there are no psychologists who specialize in OCD where you live. Personally, though, I don't know if a psychologist who specialized in OCD is really necessary, at least not at this stage.
One thing I think it is important to consider is that we no longer think of sexual orientation in terms of strictly straight or gay. We tend, nowadays, to think of sexual orientation as being on a continuum with 100% straight & 100% gay as lying at the opposite ends of the continuum. And most of us, perhaps nearly all of us really, lie somewhere in between. So, from that perspective, there's nothing out of the ordinary in what you experienced with your friend. It's simply a normal part of human sexuality... nothing to be concerned about really.
You asked what you should do. My personal, non-professional opinion would be that finding a mental health professional (perhaps a psychologist or a mental health therapist) you can talk all of this through with would really be the way to go. I think you have to open the doors & windows, so to speak, on this & let the sun shine in. If there simply is no mental health professional you can see where you live, perhaps on-line therapy might be something to consider?
Should you accept your anxiety, go forward with your life, let this obsession fade on its own, & not argue with the thoughts? Well... I don't think you should accept your anxiety. Anxiety left untreated can do a lot of damage over the long haul. (Trust me on that one okay?) Certainly there is something to be said for allowing the obsession to fade on it's own if you can manage to wait it out although, from what you wrote, it sounds as though that may be tough on you.
As far as not arguing with the thoughts goes, I would say yes trying to argue with these sorts of thoughts, or forcibly stop them, or push them back down is not a helpful way to proceed. The better alternative, to my way of thinking, would be to simply allow them to arise-&-fade at their own pace & accept them with what is sometimes referred to as compassionate abiding. Thoughts are just thoughts & we don't have to become hooked by them. We can simply acknowledge their presence when they come up, breathe into them, smile to them, perhaps even place a hand over our heart as a sign of lovingkindness for them. No big deal. Compassionate abiding is a Buddhist practice. However here's a link to a mental-health-oriented description of the practice:
Relieve Distress By Allowing It: Compassionate Abiding 101 | Mindset: Perspective Is Everything
And then here are links to 10 articles, from Psych Central's archives, that (hopefully) may be of some help:
Obsessive-Compulsive Disorder (OCD) | Psych Central
Is It Anxiety or OCD?
ERP Therapy: A Good Choice for Treating OCD
Four Steps to Manage Obsessive-Compulsive Disorder
https://psychcentral.com/blog/how-to...nful-emotions/
https://blogs.psychcentral.com/weigh...your-feelings/
https://psychcentral.com/blog/6-ways...ough-emotions/
https://psychcentral.com/lib/9-ways-...ere-right-now/
https://psychcentral.com/lib/15-smal...iety-symptoms/
https://psychcentral.com/lib/top-10-...s-for-anxiety/
My best wishes to you...
