Oh gosh, so similar to what happened to me, after 36 years marriage. He went off with another woman also in the village, and he took had been nasty and abusive. It really is the pits. I found a lot of support in online support groups, I found a great one called chump lady, for those whose spouse has gone off with someone else ( and I bet you anything your stbx has been cheating if he managed to find some else apparently so quickly. I did a lot of writing things down, so if I ever felt nostalgic I could look and see what life has been like. I joined a group for survivors of narcissistic abuse. Then there is the so many first, going back to places where we'd been together. After nearly 40 years together it would have limited my life so much if I'd avoided them all, so I tried slowly to replace with new memories, going with friends or on my own, once you've got past the first anniversary it is a bit easier. I did have some counselling, getting divorced pro weddings started just brought another set of problems, but you need to do it, you file so you can drive proceedings, if he does he will possibly stall to upset you.
Do fo and ask the doc.for help, my doc was great and the antidepressants I had did help, he upped the dose until they made an impact. I weaned myself off them when I felt better, no issues there. Talk to non friends, if you're worried about them, I did eventually find a group for women who'd suffered abuse, and the stuff you mention is coercive control, it really really helped and helped with the looking back too.
It will take time, even after nearly 12 years I still sometimes have triggers, but very slowly things will improve. I tried so many things to take my mind off things, things like I went to an archery session, something is always wanted to do, kept.on with beginner horse riding lessons, these were great because I couldn't think of anything else when I was concentrating on doing all the right things. I drove a tractor, and had a ride on my brother in law's motor trike, I started learning to roller skate at the local roller derby team, didn't get far as started worrying about falling, but I did it. I did some long walks, and went to places that I'd not been, and I knit, not a new thing but doing something easy can help keep your mind off things.
That's what I did. I tried to avoid places if I knew he might be there, and people who might 'side' with him. But if there are people who you think he might be buttering up, no harm in telling them what happened. If he stalks you or there is post separation abuse, go to the police, coercive control and stalking us a crime, keep a record of things.
And just think that what you are feeling is a normal response to what happened.
And when you are feeling up.to.it, make a start on sorting out his rubbish and chucking it, and returning anything of his to him. Get some nice new bedding that he's never seen, replace anything that was his choice with things of your choice. All the above obviously when you are feeling up to doing them