Help me with this confusing guy... ?

I really like this guy I met through my brother. We went out on a date and really hit it off. Then after about 2 weeks he started to get really distant. He called me and told me that he didn't want to see me anymore. So I did what anyone else would do, try my best to get over him. After about 2 weeks he called me and asked if I would come over because he was really depressed and needed someone to talk to. I drove over to his house and went inside. He was sitting in the dark besides the TV being on. I went up and hugged him and he didn't hesitate to hug me back. He told me about how he just gets home from work and pretty much goes to sleep until the next day. We went out for a couple drinks and I have been seeing him since. But sometimes he still gets a little distant. I don't understand it. Sometimes I think he's bipolar.. I don't know.. It just sucks because I do like him so much. I tried to talk to his sister about it and she was telling me that he has been hurt before and their family has been broken more than once. I just don't know what to think. I get so anxious about him too, he gets out of work at five and I'm counting down the minutes until he calls me. I get so antsy.. I really really need some answers!