Sending you a welcome hug
Personally I think grief is a difficult one to define. I was interested to learn that there is a manual known as the DSM, which I think is used for mental health diagnosis, which I gather from various google searches had a bereavement exclusion for a time under 'depression', I assume this represents how alot of the grief response can resemble depression and I guess to an extent expected for a period. What I'm saying here is not professional information in the slightest - just what I've gathered from google searches as I was intrigued by that question myself during my journey. If you look at the Cruse website (cruse bereavement care) they list the various feelings and include depression, and 'feelings of depression'.
Having lost someone so significant in our lives it seems that feelings of depression would be normal, I think perhaps a stage of grief is a form of depression. I know I certainly felt depressed, and after a time I did receive antidepressants from the Dr to help me cope with everything. Its difficult, nothing takes grief away quickly, we have to ride the bereavement rollercoaster, going through many stages, gradually learning how to cope
I think we are often surprised how long grief lasts and the intensity. But as long as we're gradually taking steps forward (sometimes with rests in between) we'll make it along the journey.
If you are struggling certainly pop along to your Dr and see what help they can provide. And you could consider whether bereavement counselling may be of help. I believe Cruse offers free counselling and there may be other options out there too.
We arent professionals here, just a group of people who have all lost loved ones, but that gives a safe place to be able to talk to others who understand. I found being able to talk with others, and find I was not alone in how I was feeling, helped me alot. Helps us feel less alone on this lonely journey, those further ahead on the rollercoaster are able to hold out a helping hand to those at the really hard beginning
xx