Advice On Distinguishing Mania

I know this can't take the place of medical diagnosis, but I need some advice on distinguishing possible manic symptoms. First off, I've definitely had several episodes of major depression in my life, and have been diagnosed as suffering from unipolar depression in the past. However, a part of me has always wondered if this diagnosis was incorrect, mainly because of the following slew of behaviour that I'll outline.

When I'm not depressed, there are times when I feel an elevated feeling of well-being and often seek out exercise due to the euphoria it creates. However, rather than tire me out, it leaves me with seemingly boundless energy, which leads me to seek out pleasurable activity in high doses, namely drinking alcohol and sex.

Recently, I became horrified to learn how, despite making a decent income, I have grossly failed at sticking to my budget. I tend to just buy whatever I like; not necessarily excessive shopping sprees, but my spending is greatly out of proportion to my means, because I don't seem to realize how much I've spent until some time later. This has happened repeatedly over my life, as my attitude has always been impulsive. For example, I love music, and on several occasions I've gone out and bought $100 worth of CDs I barely listen to. I read a lot, but at times I order far more books than I have time to get through, often on a whim, and they end up on my bookshelf. I've done well in school, hold a graduate degree, but decided not to continue my PhD. One reason was that I would get restless doing work. I would honestly sit down to do work, but I get distracted easily, often getting the urge to look up pointless things on the internet that just seem to pop in my head out of nowhere. This has worsened over the past few years.

This leads me to more possible symptoms. I'm very irritable, at the worst of it sometimes to the point of throwing things ( and later regretting it ), I have awful road rage, and many a time as I wait in line all I can think of is how incompetent everyone is for making the line go so slowly. In fact, there have been many times when the world seems to be going way too slowly for me. I often stay up all night surfing the internet aimlessly as I get the urge to look up pointless info. I'm a night owl, and although there have been times when I have slept a normal schedule, this never lasts long. I've never stayed up for days at a time, but there have been a few periods when I was functioning fine on a few hours of sleep for days, with little food and plenty of booze. To give one example, I used to teach at a university 2 hours from where I live, and I used to drive there in the morning after having been up all night, teach, drive home, and then go out drinking. There have also been all-nighters in which, after no sleep, I've gone out for a 10km run, before coming home and turning in.

I'm also a creative person, and have often thought that, due to my love of literature, I should write a novel. Oddly, I've often taken it as obvious in my mind that I would write something great (although I have been able to doubt this, so I'm not grossly deluded). However, the fact is, although I write well, I've never sat down to do any creative writing since I was a kid! This last revelation has dawned on me recently, and has worried me.

Basically, I'm having a hard-time distinguishing being a high-energy person from being manic, and being a confident person from having delusions of grandeur. This latter problem has been complicated by the fact that I've succeeded greatly in highly academic endeavours, so it's not like I have nothing to base the expectations I have of myself on.

I know this is long, and I apologize for rambling. Any comments and shared experiences of mania would be appreciated, especially since I've repeatedly read that it can take years to be properly diagnosed as Bipolar.