I understand where you're coming from. Sometimes I wonder why I got the mental health issues, while my two siblings were unaffected. Jealousy sometimes creeps up as I see them living normal, stable lives. However, always asking "Why me?" doesn't really help in the long run. It just keeps you stuck and bitter. I have found it more helpful to try (key word here: try) healthier perspectives and healthier actions in my life, such as being happy for my siblings that they don't have to deal with this crap. If you feel particularly down about your circumstances, try some exercise. Sounds crazy, but when you start breathing heavy and sweating, you stop thinking about that garbage and start to feel better.

Sending some hugs your way, if that's ok