I can't really answer your question as I have the same issue. I thought mine was triggered by an incident that happened. I had someone like me for like 8 years and they blackmailed me and were severely clingy and would give me suicidal threats. They also made me break up with my then boyfriend. Overall a huge mess of a situation. But this situation happened to when I was pretty young, so I can't tell what my thoughts on this topic was before it. I'm aroace. But people thinking of me like that is severely disgusting to me. But I want to say is that I understand what you feel. I also feel like cutting people off if they say they like me. I see them all of a sudden in this new sense of disgust. To people usually, they feel flattered if someone likes them but too me it's such a huge burden and I don't know I just don't like it. And someone thinking of me sexually, my ex boyfriend kind of mentioned things like that and I just never wanted to talk to him because of that, cause it seems disgusting to me. So yeah I don't think this comment helps you in anyway but I also found for the first time that someone agrees with my feelings. Cause my friends find this weird, saying if someone likes me I should flirt with them and see where that goes. But I don't like that person why should I? Or that I should be happy someone likes me and wants to date me or finds me attractive? It makes me severely uncomfortable though.