Eileithia,
It sounds like you have been through a lot. and yes our physical condition can dictate how we feel emotionally. I like you had a significant other that had depression. It was almost like an on/off switch betwen us. It's very hard to handle, but it can be done. Venting helps, jumping up and down/marching in place can help give some positve endorphines which can help elivate mood.

If you need someone to vent to, just let me know.