Bi-polar boyfriend - I need to understnd

I've been staying with my boyfriend for the last year and a half.  Absolute bliss.  He was always so gentle and kind.  He is bipolar and on meds which he drinks when and if it pleases him - he also uses alchohol sosially- now more often.  He cant sleep without sleeping medication and is hyperactive most of the time.  He resigned from his job at the end of last year just to go back the very next day on contract basis.  Since march he's been constantly complaiining that I dont notice him  - which is so not true cause I gave him every spare moment I had.  He says that my work is all that matters to me. About a month ago he started a new contract in a small town (3 hours away) - he said this will be the oppertunity to proof himself and get permanently appointed again.

2 weeks ago Sunday he was still telling me that we had such a great weekend and that it reminds him why he loves me so very very much.( 3 weeks before that he  me a huge "commitment ring") He even said that he fell in love with me all over again.  That very same evening he told me that he is moving to the small and that I need to forget about him and move on with my life.  He is a completelyy different person - doesnt want to speak to me , cold and rude.  I've NEVER seen him like this.

He was such a need freak- his ex-wife says he was the complete opposite when they were togther.  he even told his 13 yr pld daughter in january that he wont see her again because he is mad at her mother.

 What should I do we were so good togheter , but now he is a stranger to me.  he wants nothing to do with me.  Please help me to make sense from it all