Need help and guidance

I suffer from Major depression there are good days and then there are bad days. Worse than good I get up feeling like I can Conquer the world than out of the blue while I get really sad or feel like crying. This happens for no reason at all. I don't like the feeling. Let me explain a normal day for me. I wake up either more tired than when I went to sleep or in a funk to the point I stay in bed and block out the world those are the bad days. I wake up refreshed happy and feeling good about myself those are my good days I shower make breakfast and then I do things I enjoy doing. My mixed days I call them are waking up feeling good I shower make breakfast read the paper or watch the news then by the middle of the day I want to hide and cry out of the blue I go into my room or an area where no one is around and sit there. My bad days my thoughts are all over the place I feel like a failure and can't do anything right I just want to end it all and that the world would be a better place without me. My depression doesn't just affect me it also wreaks havoc on my husband, family and what little friends I have left. It's not like they support me anyways. I tried some self-help type stuff I got a room in Saint Augustine, Florida away from everyone. While on what I call a me-cation my husband asked for a divorce. We never got one and are still together. Now when I think about getting help I back out because I don't want him to leave or any thing. What do I do All my life I have tried to help everyone and do what they needed when will it be my turn to get help. Or be allowed to find myself. It also doesn't help I lost my last job because I became totally down and lost with nowhere to turn. I am wanting to get away for a week or so but with no funds, I can't and so many relying on me to be what they want and who they want.
I used to be so outgoing and had goals and dreams. A passion for things like learning, writing, taking pictures and a lot of other things I liked just sitting on the porch daydreaming about my future. Now I can't see or picture a future and anything I liked doing just faded to the point I rarely do them.
My problem is I don't know why I am depressed and it's been this way for as long as I remember even as a child in school I didn't want to talk to no one so instead I got bullied instead of being asked if I am ok. Not even the teachers noticed. My grades where horrible people just thought I was dumb or didn't care and that isn't the case I was bored.
My grandmother knew I was depressed and she would actually talk and listen along with my grandfather and the people that lived in there building. She passed away and now I have just myself I tried talking to people my mom means well but she suffers from depression as well so when we talk for some reason I get even more depressed and my husband well he doesn't understand I tried telling him the response I get is so what do you want me to do about it. My siblings in New York don't call or write they wouldn't notice that I am sick and needed help if I was right in front of them. plus they really don't have the time with kids. my siblings here every time I try to start a conversation about anything just push me away the worst part is I see that they read my messages and Ignore them. Don't get me even started on friends I had one friend from elementary school and middle school but we drifted or more like I shut her out. Others I consider friends just moved on or shut me out and in return, I shut them out.