Why else could my bbt be so erratic??

Note: I am not ttc right now. But we will be in 4 months.

So I just started temping vaginally. I was temping orally for about 6 months to track ovulation and see a pattern. But since I started temping vaginally my temps have been super erratic.

And I do take my bbt at the same time each day. I don't get up before I take my bbt. I just reach up to grab my thermometer and take it. And nothing has really changed. I mean our house isn't that much different temperature wise. So I don't know why my temps are so erratic.

Could it be because I am exercising more? Or that I changed my diet? Because my prenatal I've been taking, I've been taking it for a straight month already.

And this is my current chart.