I have intense separation anxiety from my boyfriend. I join activities, but I still feel sad. How do I deal?

I have intense separation anxiety from a boy I'll call Ilia*. He's my boyfriend. I join activities at school to help forget about my anxiety, but I still feel sad and anxious. I cry myself to sleep every night. I feel weak at school without him. I feel really sad during school. I tell Ilia* all the time about the situation. I can't function at school. He says he feels weak, too. Without Ilia*, I'm more prone to dysfunction at home because my mom's boyfriend always tries to fight with me when I'm not on the phone with Ilia*. It's like Ilia's presence is soothing and somewhat restores my sanity, like Natalie Portman and Ewan McGregor in the second STAR WARS (not the old ones with Harrison Ford, Mark Hamil, and Kerri Fisher). It's like Ilia* makes my life is better when he isn't away from me. It's like he is the only reason I'm alive. I try joining clubs and getting involved in school, but it's not distracting me from my seperation anxiety. I tried positive memory therapy, but that isn't helping me. How can I deal?