Am I bipolar or not? What's causing strange emotional state?

Do I have bipolar?

I've been confused for years, having been through a tough childhood.

I have attempted suicide once, with the most recent being late last year, resulting in cardiac arrest and a week in hospital.

I feel paranoid, argumentative. I have moods that change from severely depressed, not wanting to shower/get out of bed/etc, to euphoric, very happy and helpful.

Depression is rife in both sides of my family, with my father and mother both suffering, plus many aunties, my grandmother, and several cousins.

I have not been diagnosed with anything, as I tend to put my pride and cynical nature first, passing every attempt to get me a psychiatrist off.

Also, last year I was involved in a very serious car accident, resulting in Post Concussion Syndrome. This has affected my speech, mood, etc.

I have felt like I do for long before the accident, however, and often feel I can relate to Bipolar sufferers.

I have also had a long history of theft, starting from when I was very young, even when I had plenty of money :S.

I have also had extreme outbursts of anger, doing things like smashing my mum up against the doorway, smashing a chair on a mans chest, etc.
I feel out of control when my anger takes over, like I've been taken over, however cliche that sounds .

I apologise for the stilted format to this topic, I just don't know where to start

I would appreciate feedback on whether I'm Bipolar or not, also if you feel I'm not, what you put my feelings down to.

I understand many of you are not doctors or psychologists/psychiatrists. But I do know that many of you are affected by Bipolar, or have family members who are. Please help.