I too welcome you to the forum. Sorry to read you have experienced health issues for quite a while now. We can help and support you here, but I would like to encourage you to see a Dr about a diagnosis and reasons for the way you are feeling.
It can be hard talking to a Dr about how you are feeling. There have been times when I have written things down and handed the paper to the Dr. You could even select some of what you have written here and show that to the Dr.
Or you could Google "Symptoms of depression" and see if you match any thing listed, print out the list and take that to the Dr. The internet is a great tool, but I highly advise you discuss what you find with the Dr.
I also like to write down what is bothering me. Sometimes I have no idea, but writing at least gets the negativizes out of my mind.
Regarding reading, could you find books with short stories in them? That way reading for even 15 minutes at a time may be rewarding.
A psychologist told me that even when we don't feel like doing something, if we can push ourselves a little, then our minds create the happy endorphins which help to improve our moods. We then encourage ourselves to do something more.
It can be tough but it is worth it.
Hope you manage to make an appointment to see a Dr. You are worth it!
Cheers from Dools