Hahaha no worries
About the E.I journal, I actually started mine about now. At the time, I still had no idea what I was researching but I found that having one place to document all my thoughts was extremely helpful. From the earliest stages of E.I right up to the period where I was gathering data, I was still writing in my journal and didn't really stop until the report writing period.
To avoid your journal from becoming too messy, I recommend getting in the habit of dating all of your entries regardless of how trivial they may seem. Furthermore if you have any pre-existing files, to at least put a link somewhere in your journal for easy access. I like to think of the E.I journal as a paper trail of your research and ideas, as such it's best to use it as so. If you have any ideas or research which you find interesting, put it in because ultimately it's there to help you.
I have been documenting all of my findings thus far, however it looks as though I keep jumping from topic to topic. Is this a problem?
I would be genuinely surprise if any E.I student had a complete idea of what they were doing at this stage. To reinforce this point, even VCAA gives you to the end of term 1 to find your topic! For now, just have fun researching and developing potential ideas.