Hello!
Break ups are never easy to deal with. And it's even more difficult when you're invested till the point of marriage. So I can absolutely understand your emotions.
If the guy is still willing to make things work, you guys can even go for Couple Counselling.
If not, then you can take up therapy through a Psychologist/psychotherapist to deal with the emotions and the void created by him.
But most importantly, remember that things will not get right overnight. It's a process and you need to give yourself time for the same.
Next Steps
1. if the guy is willing, go for Couple Counselling
2. if not, visit a Psychologist/psychotherapist
Health Tips
please do not indulge in any substance use- alcohol or drugs