I am now in a relationship with a wonderful man. He was previously in another relationship, with a person suffering from depression, one who wouldn't talk about it and respond to questions with "I'm fine, just tired" sort of answers. They eventually split because he couldn't take the situation anymore. I, on the other hand, have been open about my condition since it's been diagnosed (we were together for 10 months at that point). I went through heaven and hell with him. And we're still together, and as happy as is possible.
I definitely recommend you tell your SO. Show him this post of yours for starters and allow him to ask questions. If he doesn't know anything about depression, point him to some sources -- if he doesn't read books, this is a good starting point:
http://hyperboleandahalf.blogspot.nl/20 ... t-two.htmlAs for your medical problems, why not call and say "hello, I have been depressed 6 years ago and prescribed medication, now my depression is returning, I would like to make an appointment". Then let the dr do the work from here -- they're paid for something after all.
I hope you manage to talk to your SO -- big hugs. And I hope your depressive episode doesn't last long.
Currently working on my upcoming signature.