This was me a year ago, although for different reasons.
Things that really helped were: not drinking any alcohol. Everything seemed worse when I was drunk/hungover. Plus it prevented any ridiculous decisions.
Taking some time to really look after me. I bought all the foods I usually save for a special occasion, bought new clothes, had long baths, watched my favourite films. Basically anything that gave me a hint of happiness I did.
Deleted him off everything. I mean everything - number, messages, emails, photos. I did send a few photos to my friend in case I wanted to look at them in the future, but I never did. It’s horrendous doing it, but not being able to scroll back through anything really helps in the long run.
Told my friends how hard it was and didn’t put on a brave face so they could support me appropriately. Don’t lie and say you’re ok when you’re crying every day. People like to help, let them.
Got out and about. I used to go for massive walks when I was really low and think about everything with headphones in. It helped me work through what was happening and the exercise gave me a bit of endorphins to get through the evenings.
Cried. A lot! And wrote a lot of letters I never sent.
Told myself that even if I felt horrendous right now at this very moment it wasn’t going to last forever. At some point you will be ok. And you have to concentrate on that without hiding how you feel right now.
A year on I am in a very good place and rarely think about that time in my life.
You will be ok. Honestly. Every day you will feel a tiny bit better, even if it’s a minute longer in between crying. The first few weeks are absolutely horrendous, but (and I know this sounds blasé) you’ll suddenly be 2/3/4 months down the line and realise you can’t remember how awful it was at the beginning.
Sending you lots of support and I hope this helps if only a tiny bit 