Broken Heart and in need of serious help

After 9 months together, I fell madly in love with my boyfriend and he reveled to me that he wasn’t falling in love and felt more like my best friend. He broke things off, and I am shattered. I’m 20 years old and we met in college and we have the exact same friend groups, all sharing the same best friends (he also lives across the street from me). He still wants to be best friends since for the last two months of our relationship we were basically friends but unlike him, I am suffering from a broken heart. I don’t know what to do, because I miss my best friend so much, we spent all our time together. It also has created an awkward bind in our friend group. He is understanding that its going to take me awhile to genuinely be his friend without being depressed and we overall had a clean breakup. He’s going through mental health issues and i wasn’t getting what I needed out of a relationship so I know we’re better off as friends but when I see him in the friend group all it does is make me sad. At the same time, I miss spending time with him more than life. Any advice for a broken heart when your ex still wants to be best friends?? Please help!!