I agree with the above posters that if you feel like you could benefit from talking to someone, even if just to rule out possibilities, then I say seek some professional help. It's a good starting point.

About four years ago, I started using a mood tracker app (not the one here on PC). It's called Optimism and it's free in the Apple App Store. It has many, many aspects that you can track regarding your mood, to your sleep quality, to the quality of that day's interactions with others. I also like it because it is highly customizable so if there is something that you want to track that isn't listed, you can add it (for me, I labeled a category called "silliness" because it's often when I feel like being really silly that I feel like I'm heading into a hypomanic phase of bipolar).

I started tracking my moods just out of curiosity but it actually came in handy when I had a psychologist ask me if I had ever been diagnosed as bipolar. And I hadn't, but I told her that I had been tracking my moods for the fun of it. She asked to see my chart that I generated with the app. This tracking that I had done gave her a basic idea of what I was dealing with. Then after about a year of her evaluating me and whatnot, I was officially diagnosed as BP2. So a mood tracker can actually be a very helpful addition to the diagnostic process.