my boyfriend is my Favorite Person (help)

i have bipolar disorder and i also have a boyfriend. he is my favorite person. 

i do not like it when he is away because i find myself getting progressively upset and irritable without him. i hate it! it is the worst feeling, needing someone yet them not being there. i am in shambles.

 i know he has his own life and his own friends. i take into account that i am not his world; he cannot always be here for me.

 i don't like that i am like this and i do not like how i can't stop thinking about him when he's away! >:( so therefore, i need some help. can anyone provide me some coping strategies to deal with this, please? :(