Anyone else feel like absolute shit after their period?

I've been struggling with my ferritin levels for over a year now. A few months ago, I finally got myself to a point where I'm functional (for the most part, but I still have symptoms occasionally. I've noticed that I feel the worst immediately after my period ends. A couple of days a go, I went for a few walks and a light bike ride and was still able to get through the day. I went for a short walk today and for a trip to the grocery store, and now I'm too weak physically to do anything else.