I know what you mean about guilt expressing your emotions and difficulties. I struggle with this all the time, It can really stand in the way of getting what you want/need from life. I've started diaries and become extremely concerned someone will come across it and read it (this worry was reinforced when my mum read my diary when I was 15).

As for overcoming your shame at appearing self indulgent- do you have any ideas/theories at what might have lead to your issue with guilt? I found once I explored the cause, I realised that my feelings of shame at being 'selfish' were just the result of my parents own issues and that I have no need to feel guilty for expressing my needs- it's not self indulgent, It's necessary for your life to work for you. You don't need to work around other people all the time, you don't need to please other people before you please yourself.

If you'd like to chat about it message me, It's hard to find people who understand so I'd be more than happy to talk.