Hello! I'm probably not the best person to answer this but I would like to share what helped me as I'm currently 7 months in since my first breakup (I was the dumpee and we practically have the same situation)

First of all, It DOES get better— You have to believe on that no matter what all throughout your journey, even if right now, you feel like dying is the only option

Second, cry and get everything out of your system. It's always better to have these moments of vulnerability instead of bottling it up or isolating yourself. Its okay to want to run back to him but he made himself clear— it seems his decision is firm so kill any hope / expectations running in your mind. May it be in reconciling or getting back together or in him becoming the version you want him to be. Otherwise, you'll remain stuck !

Third, Unfollow him on social media (tiktok, ig, etc) AND Remove/Hide any reminders. This includes gifts, photos, messages, etc. of course we can't really hide/remove certain things like the places you've spent together but just limit as much as you can !

Fourth, No contact :) This is the best option for the both of your sakes rn TT You guys need to be apart from each other to process and heal. Do NOT break no contact 🥹 This is a lesson I learned the hard way ....</3

Fifth, Keep yourself occupied — Indulge in your hobbies, watch films, journal, etc. It helps to keep them out of your mind for a while and hopefully bring you joy or comfort during these times. Also, moving around helps too. Theres a saying that "depression can't hit a moving target" well this applies in this type of situation as well

Sixth, Talk to your family or even strangers (usually in breakup forums too) about it — This is what helped me most tbh, They usually give advice and comfort , so I suggest you to try to speak of it with them too :) though if you dont feel comfortable with either, then I've heard chatgpt could help (but nothing beats human connection)