How open should one be in their blog

This is a question that I have been running through my head since I started this blog. How open should I be in my blog. On the one hand, I tend to be private about some aspects of my life and I don't like to share but on the other hand if I share my battles and triumphs it may help someone else who is reading it. So with some hesitation I have decided to share what is appropriate and to be open. So here it goes.
I am a fairly positive person but I have suffered with depression as well. It seems odd maybe how a positive person could go through depression but it happens I suppose. I think the times I go into depression are the times when stuff is happening and I sort of get beat down and beat down and it gets harder to stay positive until I sink down really low. I have had stuff happen that I do not feel able to share at this time that really beat me down. Other times it seems that nothing really bad has happened and yet I get into this slump that I have to fight to get out of. I have had a few major bouts of depression where I hit absolute rock bottom and there seemed to be no way out and the world seemed awful and I had no will to do anything-I didn't even want to get out of bed. It is a horrible place to be and it is not so uncommon though I felt like I was all alone and I was always paranoid that people secretly hated me. Another thing is that there seemed to be absolutely no way out and I had pretty much lost all hope. But the amazing part is that I had family that truly cared about me and supported me and did not give up on me and I did get through it.
Recently about a month ago a few seperate incidents happened that combined together brought me down pretty low. One of them was learning that an old friend had passed away who I have been wanting to reconnect with but I was too late. I will not get into the others but I have been in a slump again and I have been having difficulty getting out of it. Perhaps one of the reasons I have not gone deeper into depression is that I realize what is happening and I have worked to keep reminding myself of the blessings that I have. This is not an easy task when you are in a slump or going through depression. When I was going through depression before, well meaning people would tell me to count my blessings and how lucky I was and that would make me feel even worse because I should be happy and wasn't. But it is important to work hard to see something positive and hang on to it hard. I believe this is what has kept me from completely sinking into depression. I do not know if sharing this is going to help someone realize something or not but I felt the need to share. My positive for today was having a home that is warm and I do not have to be outside in the cold. Also that a brand new year has started with endless possibilities and that is quite amazing! Thanks for reading!