Have you cut contact with him?
Sometimes the best thing to do, in order to get someone out of your mind, even for just a split second, is to cut all the contact that you have with this person.
Hide all pictures that you have of him, delete messages he might have sent you in the past, don't call him, don't message him. Basically erase him out of your life as if he never existed. Reminders laying here and there might make it worse. It feels extremely painful, especially when you're having a good day, and then something will pop up out of nowhere that will remind you of him, and then it happens. The breakdown. The tears. The nostalgia. It is so hard.
Cutting all contact is difficult, but IMO if the person is still there, then getting over them is so much tougher and painful. It's like a wound that you pick at everyday and it never heals.
When I was going through a similar situation, I didn't get over the person. I saw every single day and every single day was as hard as the previous one. The only time I didn't think about him was during a vacation I had taken , a chance for me to get away and focus on having fun.
Focus on yourself. That is the person who is the most important. You.
Get your makeup done, get your hair done, get your nails done. Pamper yourself. Force yourself to see your friends, even when you might not feel like it.
And cry. Let it all out. The day will come when you won't feel like crying anymore. You'll have nothing left. That day might seem far away, but it will come!
(((((((((((((Hugs)))))))))))))))))))))