Hi op, mine is 10mths also. We had a run of separation anxiety there as well. Things I found helped, having a 'packed lunch' made the night before for yourself so you get lunch, ours is steady on his feet so we got a learning tower for the kitchen so he can stand beside me and watch while I cook, I wear him in a sling on days it's ready bad when I need to get things done, when I need to shower I strip him and put him in the bath seat (our shower is in our bath) at the other end with his toys and he gets a shower too, when dh comes home he takes over and I get an hour or so to myself and will chill nap or clean depending on how the day has been, I find when there's music on its easier to slip out of the room, ds goes in his bath seat in the bath when I need to pee.
Obviously there will be times when you have to leave your baby to cry and as long as its not prolonged this can help baby to build a bit of resilience. I will set ds up in his cot with his toys and music in the background and go into my room to get dressed. If he cries very hard ill go get him.
We've more or less baby proofed the nursery, our bedroom and our living room so he can crawl about the floor in those rooms while I'm doing things and keeping an eye on him. Lots of peekaboo around doors and walls helps them build reassurance that you can leave but you'll still come back.
It's totally normal for his stage of development so I try to take comfort in that he's doing what he should be and actually he has such a lovely bond with you that up to now he thought you were the same person.
Sometimes ds will cry for maybe a minute but then he'll notice his surroundings and get interested in a toy and then he's fine for 10 minutes. I think it's finding the balance between not letting them get completely distraught, but also giving them the opportunity to learn that they are safe and you will return. I sing and talk to ds from other rooms as well so he can hear me if he can't see me which is you responding even if you aren't able to pick them up right at that moment.
You need to survive parenthood as well so if you need a little time in a day to step away for the good of your mental wellbeing or to eat or pee or wash, it won't undermine all the love and attention you've given the rest of the day.