How do you balance 1) asking your partner for help, and 2) being someone they find attractive and want to date?

My GF (of 3yrs) is the happiest person in the world who I love endlessly and we’re in a very happy relationship. However, I need help and someone to talk to to. Every day , I battle suicidal thoughts. The problem is that I want her to still find me a happy, attractive person. Not some nagging, miserable, negative person - who would want to date that? 

It has nothing to do with her, or us, I just have this immense dark cloud following me. I have also had to move overseas because I could not find work in her country - which is of course one of the reasons for the dark cloud.

This has led to me switching off and avoiding her, when all that I want and need is someone to talk to. In a way it feels more lonely than having no one. 

Anyone else in this situation? Do you just tell them some of it, and pretend it’s not as severe? Nobody wants to date a negative, sad person.