When away from my bf, i have terrible Separation anxiety, HELP!?

So,whenever i'm away from my bf of 6 months,i get really strung out and needy feeling.I like try to think of every excuse to call or text him,or figure out an exccuse to go see him.And my clingyness and neediness only makes him like me less.I feel insecure a lot,which is stupid,bc every day,at the end of the day,i get him back,he never goes anywhere.I mean,i freak out if i go a day without talking to him...even half a day.I slept over last night..he went to work 30 mins ago and i'm already feeling it,thinking how i won't see him til sat night and i feel really...scared,nervous, lonely...i miss him so much.I feel like i'm torturing myself,and i try not to but it's really hard.I miss him so badly when we're apart.I have had abandonement issues in my past.So, what can i do to stop torturing myself?This is hurting my relationship.I don't wanna be a phsycho girlfriend.