Is there a way to know the breakdown of your reputation points?
- Click your linked username at the top of the page to open your user page.
- Click the Reputation tab to open the reputation graph and breakout.
- Select the entire area of the graph, or enter a date range that includes your entire SO history.
- Scroll through the list, noting how much each post contributed to your rep...
You can check your reputation graph on your profile page but it won't show everything (such as questions and answers which have been deleted, or bonus points achieved through things like associating accounts).
You can keep a more minute-by-minute track of your rep by looking at the reputation breakdown on your recent activity page as well. This will show you all the active posts you have made and the number of votes (up or down) and the total points gained or lost from the actions.