Sonja: She's trying to avoid.
Your temps really aren't fluctuating that much. Some believe that at the time of implantation there could be a dip. You had one at 6dpo which is perfect timing for implantation. I've seen a lot of dips around that time that mean nothing. Your temp dropped near your coverline, which should actually be 98.0 or 97.8 depending on how you want to handle the hollow temps.
To be honest, I'd worry more about a chart before O.

All the temps afterwards really can mean about anything. All the things that look like other pregnancy charts may or may not mean anything at all. I obsessed when I first started charting. Not any more.

I did learn a lot about cycles in general from obsessing and asking questions though. In the long run, I learned what I needed to learn from my earlier charts. I know how long my lp is. That's enough for me. Someone once told me, that what ever is going to happen is happening and a temp here and there isn't going to change the outcome. So true.
With that said, would I love to have a complete pregnancy chart? Sure, I've invested a lot of time in charting and I'd love to know if I were lucky to have more than one pregnancy chart if they were to look similar.

I need to set out my thermometer so I can start tracking pre-O temps.