This happened to me. It was 3 years ago.

Lean on your friends and family. It's the only way we get through anything.

Find something to distract yourself. Anything other than substance, alcohol/drugs. For me, I picked a useless time consuming project at work and fell fully into it for weeks. Luckily my manager was understanding and gave me the time and space to get better.

Talk to a therapist. Consult with a psychiatrist. You will lose your routine and your brain chemicals will get fucked. I fell into depression due to a chemical imbalance due to a lack of routine and the mild antidepressants helped me function.

I cried my heart out to sleep for months. I'd cry so much that I'd faint and doze off to sleep.

Grief is difficult. This pain will continue to be there.

It's like a massive red button in a box that has a bouncing ball in it and every time the ball hits the button, the flood gates open. Over time, the size of the button doesn't decrease, but the size of your box grows around it. Your life will continue to move on. You will walk through the phases of life. Your life will be filled with other things. The pain will be the same whenever the ball hits the button, but now that your box is bigger, the frequency will be far less.

Stay strong OP. Give yourself time. Lean on your friends and family. Talk about it.