Buddy I am 1000% sure you weren’t injected. Injections hurt quite a bit, especially to begin with. Also you would have to be motionless for about 5-10 seconds as it takes a while to inject the meds.
Like you say you had trousers on. In the event of getting forcibly injected they have to at least loosen your belt etc to get to your buttocks. I have seen this done to an acutely agitated patient. It takes 2-3 nurses to administer the injection.
I feel for you buddy. Sounds like your having a hard time. I know what it’s like to have unrelenting, specific fears/paranoias. You see people/events/things through a lens of suspicion and threats are everywhere.
But if I where you I would try to talk to a doctor about your fears. I note you have posted about injections multiple times which shows your fears are really troubling you. I can only speak for myself when I say meds can really help (and I don’t mean injections, I mean oral meds you take voluntarily). They have brought my a lot more clarity of thought and mostly quieter of mind.
I appreciate if you are scared of antipsychotics, cos they can have bad side effects, but if you find the right one it may give you some relief.