Hey there ): sorry you are going through a really rough time. We're here to listen whenever you need a space to talk!
As for reasons to remain optimistic? Well, that really depends from person to person. But I continue because of my love for food, my family, and my friends. And that as long as there is a fiber left in me that wants to be free of this depression, I'll fight through my days even if I'm numb because even if it's a little spark of wanting to life it can quickly grow into a flame as long as I keep feeding it. Aka as long as I have even the slightest hope about a better future I will continue.
There are always new treatments and ideas coming out since depression is now a "hot" issue so I think there is still a lot of hope
Best of luck!