I relate to this. When I was spiraling into depression, I did not even dare to vent anywhere because I have a life that is too fortunate for me to complain and reading people's stories online made me even more depressed, both from the empathetic perspective of being sorry for all the sufferings people have to endure and the selfish perspective of not even having a reason as valid and severe as theirs. I was filled by guilt of not deserving to suffer and therefore being "offensive" to and "appropriating" those who actually need help.
It takes a lot of time to get out of this mindset, but try to focus on yourself first and don't compare sufferings. You are not a saint and you can't save everyone, so at least save yourself.