So, I believe I am bipolar. I've suspected this for years now, and I've finally accepted it as a possibility. This is due to how I've noticed a cycle of my mood that has been consistent for at least the last four years. In the first few months of the year, I experience what can only be described as a manic state. Then, once the end of spring/start of summer comes along, I level out. This lasts all summer with an occasional bout of mania. Once fall starts rolling in, I feel myself becoming depressed. The depression lasts until the new year and it all begins again.

I've also compared this to my relationships over the years. They always start out with me impulsively asking someone out in the first few months. They always are shaky at the beginning and look like they won't last. Then, when I level out, the relationship gets better and has its best times. Once fall rolls in with the depression, the entire relationship just falls completely apart. Recently, as a result of all of this, I lost someone whom I cared deeply for. She was the best girlfriend I had ever had (which means that she was the manic impulsive decision I had ever made).

I'm here because I don't know what to do. I've never told anyone about this. Not even that one girl or my family. I wish I could tell her, at least, but how I was when I was depressed caused us to have these massive fights over nothing that scared her away. I can't tell my family. I just can't. I know they wouldn't be very helpful with it and that they would only use it as more ammunition against me.

I'm also trying to ignore all of the impulses that I'm feeling currently. Especially the ones involving me asking someone out. I find myself flirting without even noticing it, and two of the people who return the favor are not people I want to date. This is mainly due to how they view relationships and the people they associate with. Then there's a situation forming where I'm being set up on a date with a third girl. I'm worried that I'll give in to it and go with it, even though I still hold strong feelings for the person I ended up scaring away and hurting. And if so, doesn't she have a right to know?

Anyway, here are my questions:

1. Since I can't officially seek help yet, what all should and shouldn't I be doing to manage this?
2. If I do end up in another relationship, how should I (if I even should at all) break the news?
3. Lastly, I also deal with insomnia. So, I take 5 mg of Melatonin to try and sleep more. Will this affect my mental state at all, and if so, how?

Thanks in advance for any help!