Okay. This one might be a little personal, but its my blog! I can totally get personal. And I imagine that people have written about way worse things on the internet.
Yes, I am thankful for my period (which I did start today, btw). I didn't always feel this way. Hated it, really, for the first 10 years or so of having it. But over the last few years something changed. I started to see it as the cleansing process that it is. There's a refreshing quality to the monthly shedding. Like the change from summer to fall, I see it has a mark of another turn of the wheel, another rotation in the cycle. It's not the earth's cycle or the clock's cycle, it's MY cycle.
And it's the affirmation that I am, indeed, not pregnant, which is probably the source of the joy most women feel when I see their period has arrived. That's something that I am thankful for right now too.