Not the same, I lost my sister last december and my mum in early feb this year. Neither unexpected although Mum was really quick in the end. I do still have a sibling and a husband and 2 kids. My Dad died 20 years ago.
But I have felt fairly cast adrift ever since really. The first couple of months I felt like I was in a washing machine and didn't know which way was up.
I look at pictures and think about things from my childhood and feel very sad there's only 2 of us who really know anything about it. I feel untethered knowing there is no one 'above' me in my family so to speak (even tho Mum had dementia).
I would say, as far as you can, please please be easy on yourself. I don't know how old your DS is, or what your work/life set up is, but be as kind to yourself as you possibly can be. I have a lot of friends locally and they were all keen to meet/go for walks etc. Everything was in pencil. I had no qualms of cancelling arrangements with virtually no notice if I just wanted to lie on the sofa and cry, or sleep. Everyone understood. Even now there are certain social groups I haven't really rejoined, eg bookclub.
But then again there are some things where I think it will do me good - playing tennis for example, as you just get on with it and play, and park everything.
I found the initial grief literally exhausting physically, so as far as possible, rest, make easy food and give yourself as much of a cuddle as you can.
I really feel for you, it's so hard. Please feel free to pm if you wish.