9 years and he replaced me in 3 weeks. STRUGGLING. Please help.

Hello,
About a month ago I did a post about me and my ex partner. In brief we have been together over 9 years. We work together. We weren’t engaged/moved in but this was the year. We have both just changed our work contract to nights so we could save the last chunk of money and move out. He was going to propose on my birthday. We had a good relationship with the same goals and I thought we were set for life. Everybody thought we were set for life. We had an arguement about lockdown and didn’t speak for a week. That’s never happened before. I thought if he’s ignoring me I will ignore him (I wish I hadn’t now). I rang him a week later and he said he didn’t love me or want to be with me. No explanation just that. We spoke a bit and a few days later he said he loved me and asked what I’d told my mum and dad coz it would be awkward when we got back together so I had hope we would sort things.
A week after we stopped talking a new girl started at work and the rumours went mad. They both told me nothing was going on between them. She ended up leaving the work place after 3 weeks. He has now blocked my number, deleted me from any of his social media photos and blocked me on all social media. Him and this girl are now a couple, as in a proper couple, all the photos I have seen are them loved up and cuddling in his room, out on romantic walks kissing. It’s heartbreaking to see. After he dumped me I messaged him non stop for a few days and rang him as I wanted an explanation which I never got. Then I didn’t speak to him for 2 weeks. I saw them together and tect him saying thanks for lying about nothing going on and we ended up in an argument where he said he never wanted to speak to me again and blocked me. This is now 3 weeks ago so I haven’t spoken to him for this long. I am due to go onto nights in 3 weeks where I will have to be his manager. And I feel I have been screwed over as I was only agreeing to nights so we could get our life sorted.
Now I know we will never get back together, he had made it clear that he doesn’t care about me anymore and she is the one for him. But I am really really struggling to feel any better. From the moment I wake up I think of him and her, I can’t sleep still as my brain is in overdrive. When someone asks how I am I cry and breakdown. I need to try and make myself stronger for when I have to work alongside him. I have deleted all the photos of us, taken everything off my wall and put them in a box.
I don’t u set stand how you can throw 9 years away and be so into a new person within 3 weeks where it’s like I didn’t care. He is 34, I am 32 and she is 25. Any advice to help me start to at least feel a bit more normal would be really appreciated. As I said I know we won’t get back together. I know he won’t speak to me again but I am really struggling. Thanks.

@slk3088 If you can, change your shift. Otherwise, don’t talk to him unless it’s business related and be courteous about it.

You’re probably angry and resentful about the situation, but try to let go of bad memories and negative thoughts and pray for strength to do so…