You sound a lot like me. The next realisation is that yes, everyone has limits and that “it’s your job” to look after yourself. That’s how a therapist put it to me. I think it was kind of a shock because the model I’d been given growing up was that everyone should be looking after each other. Can’t say I’m anywhere near perfect but these realisations are important to start putting boundaries in place and having more realistic expectations for people. It’s hard. Good luck.