how to move on

I have been with my current boyfriend for 2 years i met him when i was at the lowest point in my life and every time we break up i feel like my whole world is crumbling. Yes i am only 18 but without him i feel like nothing… is this what love is ? is this what it feels like? Recently i found out my mom has brain cancer and i’ve kind of distanced myself from him because i didn’t know how to handle that. he told me he understood but now i can’t even get a reply out of him. i know he doesn’t want me anymore i can tell by the way he looks at me its not the same anymore …. and it hurts so bad i don’t want to lose him , and i feel so alone . idek if this makes any sense . if i lose him i might actually lose myself please help me