G'day Lily H,
Thanks for sharing, I've had some similar experiences.
Persons unknown spiked my drink on multiple occasions for their own reasons and each of those spikes caused me to seem psychotic; drug induced psychosis is the label the emergency department applied, and their drug tests showed what had been put into my body. Once all that left my system, the "paranoia" remained and it hurt alot.
So yeh, I feel how your thoughts are intrusive. They'll be ruminating around and around, I suppose, like mine did. In the moments the world felt weird. We got to ask ourselves... What is the evidence that someone wants to hurt me? Write it down, make a list of all the evidence you can actually see/touch and express. Maybe someone is trying to hurt you - how are they going to do that? What are your vulnerabilities? Like do you share drinks with strangers?
Do those who feed you also eat the same food? If they're eating the same food as you it's likely they want you alive!
Who provides your shelter? Removing shelter from a person is one "easy" way to harm, so if someone is providing you shelter - it's likely they want to keep you alive.
First of all attend to your bodily needs, food, water, shelter, sleep, medicines, hygiene. No matter what's going on in our head we want to stay alive, so do those things like eating, drinking and moving. Appreciate that you can do those highly important living needs. If you find you can't meet those needs every day, then head on into an emergency department or another place with people that can help.
I hope my post is useful Lily H.